❓️ `rename_allocation` via interior mutability

[h3r2tic]

Ohai, I'm not sure if this is useful to you, or a desirable change, but I thought I'd share anyway.

In our engine, we currently keep Allocations immutable, so updating their debug names isn't possible without wrapping them in some sorta mutex.

Here, I use arc-swap to allow interior mutability for the debug names.

(sorry for the noise in Cargo.toml, it got auto-formatted. I can clean it up if you're interested in the change)

[Jasper-Bekkers]

Hey tom I think these changes are useful, if you have time could you rebase them on main & drop the formatting changes in Cargo.toml?