Replace red closed icon for merge requests with closed blue icon
This came to me after writing https://gitlab.com/gitlab-org/gitlab-ee/issues/8845#note_140992336.
Reproducing that table here for easy consumption:
| Icon | Epic | Issue | Merge Request |
|---|---|---|---|
 |
Open | Open | Open |
 |
Closed | Closed | - |
 |
- | - | Closed |
 |
- | - | Merged |
The red closed icon for merge requests I think is unnecessary. It adds an extra point of complexity. Furthermore, red denotes something negative. A closed merge request is not necessarily bad. It can be actually good, since we decided that the change was not necessary (or that specific change in particular), and decided to close it. So if the goal of each merge request is to have it "resolved", then closing it is just as good as merging it. So from that perspective, the closed merge request icon should just be the blue icon with a dash, same as issues and epics. The existing merged icon looks great and is very obvious, and should definitely remain.
Also, we use red icons to indicate pipeline failures in GitLab. That is definitely a negative state. So by removing the redness of closed merge requests, we re-emphasize the severity of red and reserve that color to mean something truly bad.