I do minor history rewrites on my feature branches all the time.
1. Fix typo or other small nit.
2. `git add -p` to add only the small change.
3. `git commit -m fixer`
4. `git stash`
5. `git log --oneline main..` and copy the SHA of the commit I want to fix.
6. `git rebase -i SHA~`
7. In the text editor launched by `rebase`, move the "fixer" commit after the one I want to modify.
8. For the `fixer` commit, change "pick" to "fixup". Save and quit, allowing the rebase to complete.
9. `git stash pop`
This works most of the time, so long as the nit I want to fix isn't too far back in history. For those nits that aren't easy to fix with the workflow above, I just create an ordinary commit and leave it. It's annoying to have 5 "fixes lint error" commits in every feature branch, but it's fine to have them every once in a while.
