PR rust-lang#154634 recently renamed many type parameters that impl
`HashStableContext` as `Hcx`. It missed a few that are named `HirCtx`.
This commit renames them.

They're in multiple sections with no rhyme or reason.

`derive(HashStable_Generic)` generates impls like this:
```
impl<__CTX> HashStable<__CTX> for ExpnKind
where
    __CTX: crate::HashStableContext
{
    fn hash_stable(&self, hcx : &mut __CTX, __hasher: &mut StableHasher) {
        ...
    }
}
```
This is used for crates that are upstream of `rustc_middle`.

The `crate::HashStableContext` bound means every crate that uses
`derive(HashStable_Generic)` must provide (or import) a trait
`HashStableContext` which `rustc_middle` then impls. In `rustc_span`
this trait is sensible, with three methods. In other crates, this trait
is empty, and there is the following trait hierarchy:
```
rustc_session::HashStableContext
  |              |
  |   rustc_hir::HashStableContext
  |         /                   \
rustc_ast::HashStableContext   rustc_abi::HashStableContext
  |
rustc_span::HashStableContext
```
All very strange and unnecessary. This commit changes
`derive(HashStable_Generic)` to use `rustc_span::HashStableContext`
instead of `crate::HashStableContext`. This eliminates the need for all
the empty `HashStableContext` traits and impls. Much better.

This annotates the `Arc` type with the diagnostic attribute
`#[diagnostic::on_move]`. Now when a moved `Arc` is borrowed,
a suggestion to clone it is made, with a label explaining why.

…er of arguments

…attrs` function

…_attrs` function

…y_macro_source` function

…_macro` function

…middle_region` function

…region_outlives_predicate` function

…proc_macro` function

…f_id_and_parts` function

…field_with_def_id` function

…cBound` methods

…bound_vars` function

…ctions

…const` function

…leLapkin

tidy-alphabetical: fix line number in error message

Export `derive` at the crate root: `core::derive` and `std::derive`

This PR makes the `derive` macro available at the crate root:

```rust
#[std::derive(Clone)]
#[core::derive(Copy)]
struct X;
```

ACP: rust-lang/libs-team#766

Tracking issue: rust-lang#154645

…-items, r=GuillaumeGomez

rustdoc: seperate methods and associated functions in sidebar

fixes rust-lang#154602

r? @fmease

before:
<img width="340" height="591" alt="image" src="https://github.com/user-attachments/assets/79268155-5260-4bb9-a826-46f459fc81eb" />

after:
<img width="514" height="588" alt="image" src="https://github.com/user-attachments/assets/b56b5ca6-28d7-45a7-86a9-ad6bf37f608a" />

example of type with both (`Box`):
<img width="410" height="760" alt="image" src="https://github.com/user-attachments/assets/a74dd536-e931-4d8f-af95-275bfcf48285" />

…ooeo

Avoid creating async return opaques for foreign async fns

Fixes rust-lang#146754

Previously, def collection created the desugared async return opaque for foreign `async fn` items, but AST lowering won't lower that opaque for foreign items. That left a `DefId` without a corresponding HIR owner, which later caused an ICE during analysis.

Add a test for a past ICE when calling a const fn of an unresolved type with the wrong number of args

The ICE is fixed, but there needs to be a regression test for it.

Closes rust-lang#127423.

… r=Urgau

[rustdoc] Replace `DocContext` with `TyCtxt` wherever possible

In a lot of places, we pass down `DocContext` but actually only use its `tcx` field (`TyCtxt`). To make it more obvious what's actually being done, I replaced `DocContext` with `TyCtxt` (which implements `Copy`) in the function arguments. It created quite the cascade effect so I ended up with a lot more changes I expected.

Because it's a lot of changes, I made small commits which are easy to go through, so I strongly recommend reviewing this PR one commit at a time.

r? @Urgau