Rollup merge of #113560 - fmease:assoc-tys-in-traits-depr-wc-loc, r=compiler-errors

Lint against misplaced where-clauses on associated types in traits

Extends the scope of the lint `deprecated_where_clause_location` (#89122) from associated types in impls to associated types in any location (impl or trait). This is only relevant for `#![feature(associated_type_defaults)]`. Previously we didn't warn on the following code for example:

```rs
#![feature(associated_type_defaults)]
trait Trait { type Assoc where u32: Copy = (); }
```

Personally I would've preferred to emit a *hard* error here instead of a lint warning since the feature is unstable but unfortunately we are constrained by back compat as associated type defaults won't necessarily trigger the feature-gate error if they are inside of a macro call (since they use a post-expansion feature-gate due to historical reasons, see also #66004).

I've renamed and moved related preexisting tests: 1. They test AST validation passes not the parser & thus shouldn't live in `parser/` (historical reasons?). 2. One test file was named after type aliases even though it tests assoc tys.

`@rustbot` label A-lint

0 files changed, 0 insertions, 0 deletions