When encountering a type that needs to be pinned but that is `!Unpin`,
suggest using the `pin!()` macro.

Fix rust-lang#57994.

Signed-off-by: cui fliter <imcusg@gmail.com>

The failure and success cases are similar enough that they can share
code.

Compiling any part of the compiler will almost certainly require
Nightly.

…dtwco

Suggest `pin!()` instead of `Pin::new()` when appropriate

When encountering a type that needs to be pinned but that is `!Unpin`, suggest using the `pin!()` macro.

Fix rust-lang#57994.

a small wf and clause cleanup

- remove `Clause::from_projection_clause`, instead use `ToPredicate`
- change `predicate_obligations` to directly take a `Clause`
- remove some unnecessary `&`
- use clause in `min_specialization` checks where easily applicable

Fix broken links

The previous address is no longer available, replace it with the latest available one.

…davidtwco

Factor out common token generation in `fluent_messages`.

The failure and success cases are similar enough that they can share code.

r? `@davidtwco`

…drs, r=compiler-errors

non_lifetime_binders: fix ICE in lint opaque-hidden-inferred-bound

Opaque types like `impl for<T> Trait<T>` would previously lead to an ICE.

r? `@compiler-errors`