Fix docs-lint deprecations-and-removals CI job

What does this MR do and why?

Fix the doc generator script to move the title to the frontmatter to match the changes made in !180137 (merged)

References

Please include cross links to any resources that are relevant to this MR. This will give reviewers and future readers helpful context to give an efficient review of the changes introduced.

• gitlab-org/quality/engineering-productivity/master-broken-incidents#10315 (closed)
• https://gitlab.com/gitlab-org/gitlab/-/jobs/9035471543

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

How to set up and validate locally

Run bin/rake gitlab:docs:compile_windows and verify that there are no changes to be committed.