List conflicting files in the merge request widget
Problem to solve
When merge conflicts exist, GitLab doesn't tell me in which files the conflicts exist, which means I don't know how to approach resolving the conflicts or why the rebase isn't possible. If I have a yarn.lock file or some other machine managed file, this might be quite reasonable, expected, and can be resolved automatically with tooling, but if it is some other file I might want to investigate more deeply.
Further details
GitHub lists the conflicting files when merging/rebasing is disabled
Proposal
List the conflicting files in the merge widget