Writing good commit messages is part of your job in the sense that no reviewer should be approving anything without them, knowing that you may or may not be available if it breaks next year at 3 AM.
I put that kind of thing in the pull request, since that's where the review happens. Every commit links back to a pull request, and people actually do refer back to it. Writing good documentation there is part of the job.
No-one's going to ALSO write commit messages that no-one will see.
No-one's going to ALSO write commit messages that no-one will see.