That’s incredibly disrespectful. With that approach, I would be shocked if anyone would want to contribute to your project again after such behavior.
Accreditation for the modification of petty and trivial issues is a nice and decent gesture, but overall unworthy of a paper trail binding me to any random none-of-my-business project for such a drive-by PR.
Personally, I would feel more comfortable sending that kind of inane PRs if the parent's way of merging was the standard one, but I know it isn't and therefore opt to keep separate accounts to compartmentalize (which unfortunately increases friction to such contributions).
I don't know about others, but before investing significant time in a project, my first action will be to read through the documentation, then the code (and accompanying comments), and then I'll make minor fixes along the way.
After this, I'll submit a PR with my changes. If a maintainer were to close my patch and then proceed to commit the exact same changes under their own name, I'd never contribute, use, or improve that project again. Why would I waste my time?
That kind of behavior displays an immense lack of respect for contributors.