avoid reference count cycle in tuple extraction

[davidhewitt]

Just noticed a very minor inefficiency introduced to FromPyObject for Rust tuples which inadvertently got introduced by the change to the Bound API (and the choice to move borrowed methods to new names).

[codspeed-hq]

CodSpeed Performance Report

Merging #3976 will not alter performance

_{Comparing davidhewitt:tuple-extract (990e3e3) with main (d0f5b6a)}

🎉 Hooray! codspeed-rust just leveled up to 2.4.0!

A heads-up, this is a breaking change and it might affect your current performance baseline a bit. But here's the exciting part - it's packed with new, cool features and promises improved result stability 🥳!
Curious about what's new? Visit our releases page to delve into all the awesome details about this new version.

Summary

✅ 67 untouched benchmarks

[davidhewitt]

Will proceed to merge as this is a tiny fixup and it'd be nice to include it in the 0.21 release.