It only needs `Self::Value` and `Self::Type`, so it can be a subtrait of
`BackendTypes`. That is a smaller and simpler trait than `HasCodegen`
(which includes `BackendTypes` and a lot more).

It has `Backend` and `Deref` boudns, plus an associated type
`CodegenCx`, and it has a single use. This commit "inlines" it into
`BuilderMethods`, which makes the complicated backend trait situation a
little simpler.

It's a trait that aggregates five other traits. But consider the places
that use it.
- `BuilderMethods`: requires three of the five traits.
- `CodegenMethods`: requires zero(!) of the five traits.
- `BaseTypeMethods`: requires two of the five traits.
- `LayoutTypeMethods`: requires three of the five traits.
- `TypeMembershipMethods`: requires one of the five traits.

This commit just removes it, which makes everything simpler.

They both are part of `BuilderMethods`, and so should have `Builder` in
their name like all the other traits in `BuilderMethods`.

Some of these are pulled in indirectly, e.g. `MiscMethods` via
`TypeMethods`.

Specifically, put them where they are genuinely required, i.e. the
outermost place they can be.

Supertraits of `BuilderMethods` are all called `XyzBuilderMethods`.
Supertraits of `CodegenMethods` are all called `XyzMethods`. This commit
changes the latter to `XyzCodegenMethods`, for consistency.

This avoids some repetitive boilerplate code.

… for debug info there.

Fixes rust-lang#130063.

For example, the two following statements are desugared into a block
whose `LetStmt` source is `AssignDesugar`:

```rust
_ = ignoring_some_result();
(a, b) = (b, a);
```

…, r=bjorn3

Cleanup codegen traits

The traits governing codegen are quite complicated and hard to follow. This PR cleans them up a bit.

r? `@bjorn3`

Add zlib to musl dist image so rust-lld will support zlib compression for debug info there.

Fixes rust-lang#130063.

r? `@Kobzol`

…eyouxu

Improve handling of raw-idents in check-cfg

This PR improves the handling of raw-idents in the check-cfg diagnostics.

In particular the list of expected names and the suggestion now correctly take into account the "keyword-ness" of the ident, and correctly prefix the ident with `r#` when necessary.

`@rustbot` labels +F-check-cfg

llvm-wrapper: adapt for LLVM API changes, second try

This is a re-work of rust-lang#129749 after LLVM brought back the APIs used by rust.

No functional changes intended.

`@rustbot` label: +llvm-main
r? `@nikic`
cc: `@tmandry`

…esugar, r=compiler-errors

doc: the source of `LetStmt` can also be `AssignDesugar`

For example, the two following statements are desugared into a block whose `LetStmt` source is `AssignDesugar`:

```rust
_ = ignoring_some_result();
(a, b) = (b, a);
```