implement PyListMethods

[davidhewitt]

Split from #3606

Follows the same patterns we've seen in #3675 for the gil-ref iterator to wrap the new iterator. I think this is again extremely mechanical.

[codspeed-hq]

CodSpeed Performance Report

Merging #3680 will not alter performance

_{Comparing davidhewitt:list2 (ee1272e) with main (7f626b2)}

Summary

✅ 78 untouched benchmarks

[adamreichold]

Tiny nit w.r.t. documentation, otherwise LGTM.

[davidhewitt]

Thanks for all these reviews 🙏

I think my next step today is to write a high-level summary of the tasks remaining before I think we can release this API, so that we all have a sense of progress (and can coordinate picking up items in parallel if desired).