Auto merge of #74194 - mbrubeck:slice-eq, r=sfackler

Auto merge of #74194 - mbrubeck:slice-eq, r=sfackler

Add PartialEq impls for Vec <-> slice

This is a follow-up to #71660 and rust-lang/rfcs#2917 to add two more missing vec/slice PartialEq impls:

```
impl<A, B> PartialEq<[B]> for Vec<A> where A: PartialEq<B> { .. }
impl<A, B> PartialEq<Vec<B>> for [A] where A: PartialEq<B> { .. }
```

Since this is insta-stable, it should go through the `@rust-lang/libs` FCP process.  Note that I used version 1.47.0 for the `stable` attribute because I assume this will not merge before the 1.46.0 branch is cut next week.