Shouldn’t that be the commit message ? Or is the goal to also link forward in time, such as “we realised this commit introduced bug #123” ?
Most of the times, the commit message is 10+ lines while the change itself is -1/+1.
We use GitHub for repo hosting and a separate issue tracker to coordinate changes. It bothers me a lot that GitHub UI doesn't render markdown for commit messages. We all write really detailed and nicely formatted commit messages, and had to work out a commit message sync so the issue tracker can display related commit messages in full Markdown glory.