* Just a quick note on "wait for author":
As long as there are no conflicts and it is simple enough, we can just do the rebase from our side. It is the same effect as using a cherry-pick merge strategy, which e.g. Gerrit does by default.
It can happen (even in the book) that issues arise from references. Say in one PR someone moves a paragraph, and in another PR, further below someone else says "... as mentioned above"; with variables declared earlier, the build would fail, but with natural laguage text it is not as trivial. This is where NLP would actually help, such as LLMs / what is now called "AI".
Anyway, I suggest to then ping the author, and wait smth like 2 weeks for a reply. If the intent is clear, and the license allows for it, a maintainer may also just do their own adjusted commit, except GitHub won't allow for that direct workflow. A separate PR and mentioning the other would do then.