Blame/commit message annotations in merge request diff view

Description

It's sometimes difficult to do code review on merge requests when there are many changes, and when the motivation for those changes isn't clear.

Proposal

I propose making it possible to show "blame" in the merge request diff, so that each change is effectively annotated by the commit message which made it.

This may only make sense to me, as my habit is to make many microcommits along a branch, such that they explain each change I've made - so any feedback welcome. (Possibly the better solution is just to comment code properly.)

Mockup