Support include syntax for markdown
Problem to solve
The only way to use the same content more than once is to either duplicate it, link to it or generate the documents that reuse content. Using links is only an acceptable work-around for a limited set of cases. Duplicated content is cumbersome to manage and can quickly lead to inconsistencies. Generating Markdown for the sake of reusing content requires that the generated content is checked in in git which is not ideal. Especially when we're talking about Wiki's.
Intended users
Anyone who uses Markdown in GitLab.
Further details
Use case 1 - Reusable content
It is often the case that one piece of content is being used in several places inside the same document or throughout several documents. Think of content such as contact information, a list of variables, logo's, warnings, disclaimers etc.
Use case 2 - Reference generated content
Certain Markdown documentation is often generated. Instead of having to resort to a link to the generated Markdown document or copy a piece of static Markdown in the generated content through code it's more practical to include it by referencing it from a static Markdown document. The main benefit of this is that the content doesn't have to be generated every time the static content changes.
Proposal
I propose supporting syntax for including Markdown documents inside other markdown documents that are part of the same project.
I've found the markdown-include extension as an example which uses the following syntax:
Source file
# Heading Level 1 of main file
{!included_file.md!}
## Heading Level 2 of main file
{!included_file.md!}