add #[inline] hints on many Bound and Borrowed methods

[davidhewitt]

When looking at the codspeed benchmark for #4016 I noticed that we were missing #[inline] on many basic operations on Bound and Borrowed which probably make sense to be #[inline].

Let's see if this reports any meaningful improvements...

[codspeed-hq]

CodSpeed Performance Report

Merging #4024 will improve performances by 24.24%

_{Comparing davidhewitt:inline-borrowed (34764a3) with main (74d9d23)}

Summary

⚡ 1 improvements
✅ 67 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	davidhewitt:inline-borrowed	Change
⚡	drop_many_objects	68.6 µs	55.2 µs	+24.24%

[davidhewitt]

Seems like this does help a little, so let's proceed 😁