Fix conflict highlighting
What does this MR do?
Fixes conflict highlighting in 10.2. No issue, @DouweM just noticed it.
Are there points in the code the reviewer needs to double check?
The spec is ugly, but the best option I can think of.
Why was this MR needed?
Before https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/14747, conflicts used a Repository
. Then, when highlighting, #gitattribute
got called on that repository, to find a custom language if needed.
After that MR, we were now using a Gitlab::Git::Repository
instead, which didn't have a #gitattribute
method. Gitlab::Highlight
has an unconditional rescue
that falls back to plain text, so nothing blew up - conflicts were just not syntax-highlighted.