Rollup merge of #144194 - estebank:const-traits, r=davidtwco

Provide additional context to errors involving const traits

When encountering an unmet `Ty: [const] Trait` bound, if `Trait` is `#[const_trait]` and there's an `impl Trait for Ty` point at it. If local, suggest `impl const Trait for Ty`, otherwise just point at it.

```
error[E0277]: the trait bound `NonConstAdd: [const] Add` is not satisfied
  --> $DIR/assoc-type.rs:37:16
   |
LL |     type Bar = NonConstAdd;
   |                ^^^^^^^^^^^
   |
note: required by a bound in `Foo::Bar`
  --> $DIR/assoc-type.rs:33:15
   |
LL |     type Bar: [const] Add;
   |               ^^^^^^^^^^^ required by this bound in `Foo::Bar`
help: make the `impl` of trait `Add` `const`
   |
LL | impl const Add for NonConstAdd {
   |      +++++
```
```
error[E0277]: the trait bound `T: [const] PartialEq` is not satisfied
    --> tests/ui/traits/const-traits/call-generic-method-fail.rs:5:5
     |
5    |     *t == *t
     |     ^^^^^^^^
     |
note: trait `PartialEq` is implemented but not `const`
    --> /home/gh-estebank/rust/library/core/src/ptr/const_ptr.rs:1590:1
     |
1590 | impl<T: PointeeSized> PartialEq for *const T {
     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: trait `PartialEq` is implemented but not `const`
    --> /home/gh-estebank/rust/library/core/src/ptr/mut_ptr.rs:2011:1
     |
2011 | impl<T: PointeeSized> PartialEq for *mut T {
     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
```

Author: Zalathar