Docs: Fix Vale issues with the CI/CD environment variables doc

Problem to solve

The Vale linter is used to support grammar linting in GitLab documentation. As Vale was implemented after many of the GitLab documents were written, we have many documentation pages that do not meet the linting standards created by the GitLab Technical Writing team for Vale.

Further details

As an example, here's the output from a Vale test on the CI/CD environment variables topic, which is in the docs here.

You don't need to fix all of these issues; fix as many as you can.

The first number is the line number in the doc file where you can find the issue.

 77:34     warning     Avoid using future tense:       gitlab.FutureTense
                       "will be"
 78:30     warning     Avoid using future tense:       gitlab.FutureTense
                       "will be"
 123:66    warning     Avoid using future tense:       gitlab.FutureTense
                       "will only"
 124:75    warning     Avoid using future tense:       gitlab.FutureTense
                       "will be"
 140:12    warning     Avoid using future tense:       gitlab.FutureTense
                       "will be"
 190:59    warning     Avoid using future tense:       gitlab.FutureTense
                       "will be"
 311:20    warning     Avoid using future tense:       gitlab.FutureTense
                       "will also"
 379:76    warning     Avoid using future tense:       gitlab.FutureTense
                       "will be"
 422:70    warning     Avoid using future tense:       gitlab.FutureTense
                       "will be"
 424:25    warning     Avoid using future tense:       gitlab.FutureTense
                       "will be"
 444:21    warning     If possible, use                gitlab.SubstitutionWarning
                       "administrator" instead of
                       "admin".
 450:65    warning     Avoid using future tense:       gitlab.FutureTense
                       "will only"
 451:74    warning     Avoid using future tense:       gitlab.FutureTense
                       "will not"
 451:118   warning     Avoid using future tense:       gitlab.FutureTense
                       "will not"
 543:13    warning     Avoid using future tense:       gitlab.FutureTense
                       "will take"
 550:5     warning     Avoid using future tense:       gitlab.FutureTense
                       "will also"
 588:79    warning     Avoid using future tense:       gitlab.FutureTense
                       "will then"
 696:50    warning     Avoid using future tense:       gitlab.FutureTense
                       "going to compare"
 706:42    warning     Avoid using future tense:       gitlab.FutureTense
                       "will evaluate"

Proposal

Who can address the issue

Other links/references