As a maintainer who sometimes requests PR submitters to make style changes or even squash their PRs: Please tell me you don't want to finish it so that I can do so.

I am reluctant to merge your PR if it has too many style issues or improper commit history. The last 10% can be important when maintaining a large project.

Because of the way git/github work, modifying someone else's PR (by pulling locally + modifying + resubmitting as a new PR) often means their authorship in the commit headers is erased, and I wouldn't want to do that without permission.