Auto merge of #150640 - AprilNEA:mgca-merge-associated-const-equality, r=BoxyUwU

Merge `associated_const_equality` feature gate into MGCA

Tracking Issues: rust-lang/rust#132980 rust-lang/rust#92827

Merge `associated_const_equality`(ACE) feature gate into `min_generic_const_args`(MGCA).

- Replaces `features().associated_const_equality()` checks with `features().min_generic_const_args()`
- Updates the parser to gate associated const equality under `min_generic_const_args`
- Moves `associated_const_equality` to the removed features list
- Removes the `associated_const_equality` method from the `Features` trait
- Updates all affected tests and tools (rust-analyzer, clippy)

Closes rust-lang/rust#150617

r? `@BoxyUwU`

Author: bors

crates/hir-ty/src/lower.rs

@@ -850,7 +850,7 @@ impl<'db, 'a> TyLoweringContext<'db, 'a> {
                                 TermKind::Ty(ty) => {
                                     ty.walk().any(|arg| arg == dummy_self_ty.into())
                                 }
-                                // FIXME(associated_const_equality): We should walk the const instead of not doing anything
+                                // FIXME(mgca): We should walk the const instead of not doing anything
                                 TermKind::Const(_) => false,
                             };