Docs feedback: Explicitly state reduce repo size impact on GitLab UI elements

Documentation Page: https://docs.gitlab.com/ee/user/project/repository/reducing_the_repo_size_using_git.html

Although this process technically works, it also fails to mention that it knowingly breaks the GitLab UI, resulting in 404's for things like the Merge Requests Changes and Commits tabs. The underlying source code intentionally makes no effort to utilize the New commit-ids to update the internal GitLab database tables.

This is rather significant, and worth having a warning banner of some sort on the page to indicate as much.

Thanks