Enforce and lint for language tags for all code blocks

Proposal

We should work towards enabling rule 40 in markdownlint, and enforce that all codeblocks should have a language specified.
You test languages at http://rouge.jneen.net/
Known languages that we have used so far:
```plaintext: When no language. Also used for output from shell commands. Replace text with this.
```JavaScript: Replace js with this
```html
```ruby: Replace rb with this
```shell: Replace bash and sh with this.
```toml: Config files, like with Runner docs
```ini: Simple config files, when not TOML (sometimes). Replace conf with this?
```prometheus: Prometheus config
```yaml: Replace yml with this
```sql
```asciidoc
```dockerfile: Replace docker with this
```erb
```elixir
```golang: Replace go with this
```graphql
```html
```http
```haml
```json: Replace json-doc (broken) with this
```markdown: Replace md with this
```mermaid
```nginx
```python
```php
```perl
```TypeScript: Replace ts with this.
```xml
Current list of ~~1270~~ ~~1174~~ ~~691~~ ~~397~~ ~~256~~ ~~204~~ 105 code blocks found by markdownlint that are missing a language tag and must be fixed before the rule can be enabled (NOT including charts/omnibus/runner):
Click me to collapse/fold.
administration/geo/replication/troubleshooting.md:615 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "   ```"]
administration/high_availability/database.md:923 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "  ```"]
administration/high_availability/database.md:933 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "  ```"]
administration/repository_storage_types.md:96 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
administration/repository_storage_types.md:129 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
administration/troubleshooting/postgresql.md:139 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
api/deploy_tokens.md:85 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
api/deploy_tokens.md:122 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
api/deploy_tokens.md:147 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
api/deploy_tokens.md:186 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
api/deploy_tokens.md:225 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/documentation/index.md:450 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/documentation/styleguide.md:526 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/documentation/styleguide.md:1362 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "  ```"]
development/elasticsearch.md:187 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/elasticsearch.md:198 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/elasticsearch.md:204 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/elasticsearch.md:211 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/experiment_guide/index.md:61 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "  ```"]
development/fe_guide/development_process.md:15 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/fe_guide/graphql.md:152 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/fe_guide/graphql.md:161 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/fe_guide/style/vue.md:297 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "   ```"]
development/fe_guide/tooling.md:67 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/fe_guide/tooling.md:78 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/fe_guide/tooling.md:84 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/fe_guide/tooling.md:90 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/fe_guide/tooling.md:96 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/fe_guide/tooling.md:106 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/fe_guide/tooling.md:112 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/fe_guide/vue.md:28 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/fe_guide/vuex.md:25 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/feature_flags/controls.md:15 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/feature_flags/controls.md:73 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/feature_flags/controls.md:95 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/feature_flags/controls.md:120 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/feature_flags/controls.md:126 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/feature_flags/controls.md:134 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/file_storage.md:63 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/geo.md:137 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/geo.md:149 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/geo.md:202 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/geo.md:208 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/geo.md:255 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/gotchas.md:104 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "  ```"]
development/i18n/externalization.md:491 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/import_export.md:66 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/import_project.md:151 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/instrumentation.md:90 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/integrations/jira_connect.md:34 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "      ```"]
development/internal_api.md:37 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/internal_api.md:60 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/internal_api.md:106 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/internal_api.md:129 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/internal_api.md:141 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/internal_api.md:164 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/internal_api.md:176 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/internal_api.md:193 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/internal_api.md:205 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/internal_api.md:229 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/internal_api.md:241 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/internal_api.md:272 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/internal_api.md:284 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/internal_api.md:304 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/internal_api.md:316 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/new_fe_guide/development/accessibility.md:30 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/new_fe_guide/tips.md:7 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/routing.md:10 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/routing.md:16 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/routing.md:32 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/routing.md:43 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/routing.md:59 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/shell_commands.md:74 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/shell_commands.md:84 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
development/shell_commands.md:206 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
install/installation.md:341 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "   ```"]
integration/gitlab.md:18 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "   ```"]
integration/gitlab.md:66 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "   ```"]
integration/google.md:31 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "     ```"]
integration/jenkins.md:163 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
integration/kerberos.md:36 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
integration/kerberos.md:246 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
integration/kerberos.md:285 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
integration/oauth2_generic.md:29 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "   ```"]
integration/recaptcha.md:26 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
integration/salesforce.md:63 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "   ```"]
integration/saml.md:132 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
integration/shibboleth.md:69 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "   ```"]
integration/shibboleth.md:104 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
raketasks/user_management.md:55 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
security/rack_attack.md:180 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "   ```"]
security/rack_attack.md:186 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "   ```"]
topics/airgap/quick_start_guide.md:153 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
topics/autodevops/quick_start_guide.md:242 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
university/training/user_training.md:297 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
user/application_security/dast/index.md:221 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
user/application_security/dast/index.md:241 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
user/application_security/dast/index.md:476 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
user/application_security/sast/index.md:520 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
user/asciidoc.md:20 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
user/packages/npm_registry/index.md:227 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
user/project/clusters/serverless/aws.md:143 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
user/project/code_owners.md:32 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
user/project/code_owners.md:71 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
user/project/new_ci_build_permissions_model.md:216 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
Edited Mar 24, 2020 by Marcel Amirault