I do see your point (not bloat BPO with a one line fix per each undocumented feature), but IMHO it's somewhat unrealistic to fix all issues of the same type in a single PR.

I opened this PR because I was reading this particular function and noticed that the "size" parameter is documented as required. If it was documented as optional, the default value is not documented either.

Perhaps we can compromise, and I can look at all the classes/functions in "io", and improve this PR? I cannot propose myself to do this to the whole Python documentation at once :/

Excuse me if I didn't interpret your comment right.