Show the head commits shas when the merge is prevented due to multiple heads
Right now when there are multiple heads, RC shows a message:
Merge is not currently possible because of below failed checks.
- This pull request cannot be merged because the target has multiple heads.
It is difficult to know which commit is causing this. It would be nice to know this information in the warning above.
Also, when this situation happened, in my case there were multiple heads in the source repo. So I think the warning has to consider whether it is the source repo (originating the PR) or the target repo (the destination for the PR).