bpo-44353: Correct docstring for `NewType` (GH-29785)


The docstring for `typing.NewType` is no longer strictly accurate, now that `NewType` is a class, rather than a function
(cherry picked from commit 93c65df83cef71a4bc77d71afecdec8744c4f73a)

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
1 file changed