[Python-Dev] Documenting collections.abc __class_getitem__ type hints

I'm looking through the documentation, and not finding any good reference for type hints for __class_getitem__ in the collections.abc module. I do see some of it covered in the typing module documentation, but those are deprecated, and some are somewhat cryptic (e.g. Coroutine). Make sense to open a BPO and start a PR for doc updates? Paul