fix: handle lifetime variables in `CallableSig` query
Fixes#13838
The problem is similar to #13223: we've been skipping non-empty binders, letting lifetime bound variables escape.
I ended up refactoring `hir_ty::callable_sig_from_fnonce()`. Like #13223, I chose to make use of `InferenceTable` which is capable of handling variables (I feel we should always use it when we solve trait-related stuff instead of manually building obligations/queries).
I couldn't make up a test that crashes without this patch (since the function I'm fixing is only used *outside* `hir-ty`, simple `hir-ty` test wouldn't cause crash), but at least I tested with my local build and made sure it doesn't crash with the code in the original issue. I'd appreciate any help to find a regression test.
This makes code more readale and concise,
moving all format arguments like `format!("{}", foo)`
into the more compact `format!("{foo}")` form.
The change was automatically created with, so there are far less change
of an accidental typo.
```
cargo clippy --fix -- -A clippy::all -W clippy::uninlined_format_args
```
I am not certain if this will improve performance,
but it seems having a .clone() without any need should be removed.
This was done with clippy, and manually reviewed:
```
cargo clippy --fix -- -A clippy::all -D clippy::redundant_clone
```
Two breaking changes:
- `TypeFolder` has been split into `TypeFolder` and `FallibleTypeFolder`
- `ProjectionTy::self_type_parameter()` has been removed
