Server-side amends for MR link
In the Git world, one of the advantages of explicit merge commits upon MR acceptance is to play the role of the cover letter that some email-based workflow use: namely, a summary of what the entire series of changesets does.
I've been reluctant to use the semi-linear merge method because it is heavy handed for MRs that consist of exactly one commit. But the MR can have interesting discussions. In some cases, most of the motivation behind the changes is actually in the MR description and comments.
So here's an idea: for MR with a single changeset and semi-linear method, the server could amend the unique changeset to add the MR link. Maybe we could do that as well in other cases (squash come to mind, but it's already almost there, with the message of the resulting commit being under user control).