rename "object safety" to "dyn compatibility"

[Veykril]

rust-lang/lang-team#286

We have a diagnostic for this now, as well as a hover message that use object safety as the term, we should change that if this goes through.

[noahmbright]

Is this as simple as scrubbing the code base for "object_safety", "ObjectSafety", and what not and swapping with dyn_compatibility? I can take care of this if that's the case

[alibektas]

Almost. You can check https://github.com/rust-lang/rust-analyzer/tree/master/crates/hir-ty/src/object_safety and see which other parts refer to this part of the codebase change every reference, usage of words "Object Safety" etc.

You can assign yourself by using [at]rustbot claim command as a comment

[noahmbright]

@rustbot claim

Got it. I think between grep, the compiler and a reviewer I can get this taken care of. Hopefully the former 2 make it easy on the latter