Auto merge of #34443 - eddyb:sized-matters, r=arielb1

Auto merge of #34443 - eddyb:sized-matters, r=arielb1

Disallow constants and statics from having unsized types.

This is a `[breaking-change]` which fixes #34390 by banning unsized `const` and `static`, e.g.:
```rust
const A: [i32] = *(&[0, 1, 2] as &[i32]);
static B: str = *"foo";
```

This was not intentionally allowed, and other than for `static` since some versions ago, it ICE'd.
If you've been taking advantage of this with `static`, you should be able to just use references instead.