add `PyFloat::new_bound` #3773

Performance Regression: -53.12%

⚡ 3 improvements
❌ 4 regressions
✅ 73 untouched benchmarks

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

	Benchmark	`main`	`davidhewitt:float-new-bound`	Change
❌	`extract_float_extract_success`	408.9 ns	464.4 ns	-11.96%
❌	`extract_float_downcast_success`	418.9 ns	474.4 ns	-11.71%
⚡	`extract_int_downcast_fail`	266.1 ns	238.3 ns	+11.66%
⚡	`test_simple_py`	34.7 µs	31.4 µs	+10.48%
❌	`f64_from_pyobject`	359.4 ns	766.7 ns	-53.12%
⚡	`not_a_list_via_downcast`	211.7 ns	183.9 ns	+15.11%
❌	`list_via_downcast`	157.2 ns	185 ns	-15.02%