adjust path for GIL Refs deprecation warnings

[davidhewitt]

I noticed that the UI tests are emitting warnings like

error: use of deprecated method `pyo3::methods::Extractor::<T>::extract_gil_ref`: use `&Bound<'_, T>` instead for this function argument

That pyo3::methods path bothered me as I want to deprecate that module (probably a 0.22 thing at this point). I thought we might be able to get something more meaningful, so I shuffled code around a little. Now we get:

error: use of deprecated method `pyo3::deprecations::GilRefs::<T>::extract_gil_ref`: use `&Bound<'_, T>` instead for this function argument

Do folks think this is any nicer? Think we can make the path even better for readers?

cc @Icxolu as this probably will have merge conflicts with code you're typing 😬

[Icxolu]

In my opinion this does look nicer, and separating the construct used purely for deprecation warnings makes sense, so that we can easily find them when it's finally time to remove the, again.

[davidhewitt]

Great! I'll rebase this once #3967 goes in and get this merged 👍

(Probably first thing in the morning now.)