Do not use absolute URLs like `https://docs.gitlab.com/ee/index.html` to crosslink
to other docs within the same project. Use relative links to the file, like `../index.md`. (These are converted to HTML when the site is rendered.)
Relative linking enables crosslinks to work:
- in Review Apps, local previews, and `/help`.
- when working on the docs locally, so you can verify that they work as early as possible in the process.
- within the GitLab UI when browsing doc files in their respective repositories. For example, the links displayed at <https://gitlab.com/gitlab-org/gitlab/-/tree/master/doc#gitlab-docs>.