Replaces all the explicit include metadata syntax in the specs (tag:
true) into the implicit one (:tag).
Added a cop to prevent future errors and handle autocorrection.

The helper creates a fork of a project with all provided attributes,
but skipping the creation of the repository on disk.

Signed-off-by: Rémy Coutable <remy@rymai.me>

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/32424

Bug introduced in
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11327

The problem is that we often go via a diff object constructed from the diffs
stored in the DB. Those diffs, by definition, don't overflow, so we don't have
access to the 'correct' `real_size` - that is stored on the MR diff object
iself.

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/31276