> Obviously commits like "fixed review comments" or "removed some left-over comments" or "fixed typo" should not be pushed into a PR you asked others to review.

Could you explain this a bit more? I'm having trouble visualizing the end to end process.

1. Someone has what they feel is a complete change and submits a PR for review.

2. The reviewers read part of it, first half looks good, and halfway through they have concerns and request changes.

3. The submitter now has to fix those concerns. If they are not allowed to push an additional commit to do this, how do you propose they accomplish this? Certainly they should not force push a public branch, right? That would cause pain to any reviewer who fetched their changes, and also break the features on GitHub such as them marking which files they have already read in the UI. But if we cannot push new commits and we cannot edit the existing commits, what is the method you are suggesting?