networkx: Update usages of SupportsGetItem that should be more restrictive

[Avasam]

Checked against the implementation to see when SupportsGetItem wasn't enough.

Will also reduce changes from #14038

CC @darabos since you added most of these in #13458 . Feel free to re-validate against the implementation.

[darabos]

Looks great to me! Thank you!

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉

[srittau]

I'm not a fan of replacing protocols with ABCs, especially if they're as broad as Mapping. Can't we use broader protocols?

[Avasam]

I can re-review usage. Mixing mapping-based protocols is quite annoying at the moment (without Protocol Intersection), and we may be getting too close to implementation details, where I'm not sure it's worth creating new (and/or combined) protocols just for this. But I'll see.

[srittau]

My main beef with Mapping (and Sequence) is that it's not a protocol. Maybe it would make sense to add a MappingLike protocol to _typeshed that includes commonly used methods (like __getitem__, keys etc.).

[srittau]

Let's go with Mapping for now. We can always replace them later if #15146 gets merged and has made its way into type checkers.

[Avasam]

Thanks. And I think you meant #15152