Port #[rustc_autodiff] to the attribute parser infrastructure

[JonathanBrouwer]

For #131229

r? @jdonszelmann
cc @ZuseZ4

autodiff_forward and autodiff_reverse can be ported in a seperate PR, but these are expanded in the AST and don't exist anymore in the HIR so this is a bit more of a challenge.

[rustbot]

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

Some changes occurred in compiler/rustc_passes/src/check_attr.rs

cc @jdonszelmann

Some changes occurred in compiler/rustc_ast/src/expand/autodiff_attrs.rs

cc @ZuseZ4

Some changes occurred in compiler/rustc_hir/src/attrs

cc @jdonszelmann

Some changes occurred in compiler/rustc_codegen_llvm/src/builder/autodiff.rs

cc @ZuseZ4

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann

Some changes occurred in compiler/rustc_builtin_macros/src/autodiff.rs

cc @ZuseZ4

[rustbot]

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[JonathanBrouwer]

@jdonszelmann Rebased :)