Consistently mark types with `| MaybeNone` whenever it is applicable

I noticed that there's a special type alias MaybeNone that represents this specific intent:

We didn't dare to change the type to X | None so instead we changed it to Any

You can find an example in a relatively recent addition of this.

And while this approach makes me very sad, it is good that such cases are marked with MaybeNone, for the purpose of looking at them specially. Maybe some type checker will arise that will have specific handling for it and do something smarter instead.

With that in mind, it would be good to ensure that all such cases are consistently marked.

I noticed at least one case that is not marked like this. It has | Any directly written instead of | MaybeNone. This is in re.match.group*:

https://github.com/python/typeshed/blob/6feca188689e14cdacd8dbf8bc9cf0635993027a/stdlib/re.pyi#L93-L117

Bắt đầu với stdlib/re.pyi, đặc biệt là các định nghĩa re.match.group* quanh dòng 93–117, và so sánh chúng với alias MaybeNone trong stdlib/_typeshed/init.pyi. Xem xét các trường hợp tương tự trong các stub, nơi ý định này được biểu diễn bằng Any; hoàn thành nghĩa là các trường hợp áp dụng đều nhất quán sử dụng MaybeNone thay thế và không tìm thấy ngoại lệ nào không được đánh dấu.