You can not highlight text in a commit message and leave an in-line comment in the same way you can for code changes in the diff.
Ohhhhh you can’t comment on a specific line of a commit message. I see. I mean… yeah I guess not. That seems like a super niche feature though. How long are your commit messages? I’ve never even tried to do that. Commit messages are short enough you can pretty much just write a normal message not tied to a specific line.
There are waaaaay bigger issues with Gitlab. Here’s one I ran into recently, you can’t search for pipelines. It’s got a search box and everything but you literally can’t search; only filter. So stupid.
I actually just went to take a look at Gitlab issues I have commented on to see what my worst ones are. Guess what… you can’t even search for issues you have commented on!!!
Still, overall it’s the best self-hostable option out there at the moment IMO. I guess Forgejo (truly abysmal name) may overtake it at some point.