I think it does a better service to users to explain how Python returns None implicitly if a function doesn't have any other explicit return value.  If the print() docs had this note, it would be confusing why other similar functions don't.

It's also worth explaining that when a function is designed to *explicitly* return None in certain cases (e.g. dict.get()) that it shouldn't do so implicitly, but should include an explicit `return None` for readability.