Highlight merge requests with unresolved discussions

Problem to solve

#8436 (closed) displays merge request approvals in the merge request list, which is extremely helpful for quickly finding merge requests that can be merged. However, our repository configuration disallows merging branches with unresolved discussions, so the green approvals count can be deceiving when the MR is approved, but there are discussions outstanding.

Intended users

Developers, maintainers and release managers

Proposal

A solution could be to also colorize the comments count, similar to the way the approvals count is displayed now - maybe black for no outstanding discussions and yellow when there are outstanding discussions?

What does success look like, and how can we measure that?

It's easy to look at the list of merge requests and see which ones can, in fact, be merged