use smallvec instead of inplace_it

[mockersf]

Checklist

• Run cargo clippy.
• Run RUSTFLAGS=--cfg=web_sys_unstable_apis cargo clippy --target wasm32-unknown-unknown if applicable.
• Add change to CHANGELOG.md. See simple instructions inside file.

Connections

Description
Remove inplace_it to use smallvec instead. While inlace_it tries to be clever with the size of the array used, I just set it to 32 in smallvec
On latest nightly, inplace_it fails to compile. This will probably be fixed on Rust (rust-lang/rust#99288) or inplace_it (NotIntMan/inplace_it#11), but inplace_it hasn't been updated in a while.

Testing
This is Vulkan only change and I don't have a Vulkan capable machine, so not tested a lot...

[notgull]

Could we use tinyvec instead and reduce the unsafe code surface?

[mockersf]

I went with smallvec as it's already in tree

[cwfitzgerald]

I'm just going to say this is fine for now - we really should revisit this stuff later if we have a more coherent allocation solution.