Make os.Pathlike more similar to a Protocol

[tungol]

Feature or enhancement

Proposal:

#83066 considered making os.Pathlike a protocol, but rejected the idea due to not wanting to import typing into os.py.

As an alternative, I propose making more it more protocol-like in two ways:

1. add it to typing._PROTO_ALLOWLIST so it can be used as a base class in other protocols
2. use class PathLike(metaclass=abc.ABCMeta) instead of class PathLike(abc.ABC). This aligns with the other protocol-like ABCs in collections.abc. Actual protocols do have that metaclass but don't have the abc.ABC base class. Doing this makes it a little smoother for typeshed to define the class as class PathLike(Protocol) in the stubs.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-126705: Make os.PathLike more like a protocol #126706