allow from_py_with on function args to take a fn(&Bound) -> PyResult

[Icxolu]

Part of #3684

This allows the #[pyfunction] and #[pymethod] arguments to use Bound API extractors in #[pyo3(from_py_with = ...)]. I reused the internal Extractor implementation that I recently introduced in #3828. For now I left it where I added it initially, but if we like to move it to a different place or module, I can do that.

There is still a lot of old APIs surrounding this, but it might be better to tackle them separately.

[codspeed-hq]

CodSpeed Performance Report

Merging #3837 will degrade performances by 15.63%

_{Comparing Icxolu:from-py-with-pyfunction (1a4a44d) with main (0c12d91)}

Summary

⚡ 1 improvements
❌ 3 regressions
✅ 75 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	Icxolu:from-py-with-pyfunction	Change
❌	mapping_from_dict	300 ns	355.6 ns	-15.63%
⚡	f64_from_pyobject	461.1 ns	405.6 ns	+13.7%
❌	sequence_from_list	327.8 ns	383.3 ns	-14.49%
❌	sequence_from_tuple	232.8 ns	260.6 ns	-10.66%

[davidhewitt]

Thanks, that was straightforward!

There is still a lot of old APIs surrounding this, but it might be better to tackle them separately.

If you mean the rest of extract_argument, I've got pretty much all of it in #3708. That's just blocked on #3802 and then I think it's finally mergeable. I'll try to update #3802 tonight, if my toddler ever settles down for bed... 🙃

[davidhewitt]

Given that Extractor should be just temporary code which we'll remove again when the GIL Ref API is dead and gone, I'm fine with leaving it here for now 👍