disable markdown in comments when referencing disabled features
fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/23548
This MR prevents the following references when tool is disabled:
- issues
- snippets
- commits - when repo is disabled
- commit range - when repo is disabled
- milestones
This MR does not prevent references to repository files, since they are just markdown links and don't leak
information.
See merge request !2011
Signed-off-by: Rémy Coutable <remy@rymai.me>
1. We can create the note directly on the issue, rather than attaching
it after creation.
2. We need to update the MergeRequestClosesIssues relation to ensure
that the issue know that it's closed by the MR.
3. We should also check that the unavailable button is displayed - not
just that the available button is displayed.
This button depends on Issue#can_be_worked_on? which in turn depends on
Issue#related_branches. By rendering this button asynchronously we can
finally remove all usages of Issue#related_branches and
Issue#referenced_merge_requests from the issues "show" page.
