Rollup merge of #125168 - Jules-Bertholet:match-ergonomics-2024-align-with-rfc, r=Nadrieril

Match ergonomics 2024: align implementation with RFC

- Remove eat-two-layers (`ref_pat_everywhere`)
- Consolidate `mut_preserve_binding_mode_2024` into `ref_pat_eat_one_layer_2024`
- `&mut` no longer peels off `&`
- Apply "no `ref mut` behind `&`" rule on all editions with `ref_pat_eat_one_layer_2024`
- Require `mut_ref` feature gate for all mutable by-reference bindings

r? ``@Nadrieril``

cc https://github.com/rust-lang/rust/issues/123076

``@rustbot`` label A-edition-2024 A-patterns

compiler/rustc_feature/src/unstable.rs

@@ -529,8 +529,6 @@ declare_features! (
     (unstable, more_qualified_paths, "1.54.0", Some(86935)),
     /// Allows the `#[must_not_suspend]` attribute.
     (unstable, must_not_suspend, "1.57.0", Some(83310)),
-    /// Make `mut` not reset the binding mode on edition >= 2024.
-    (incomplete, mut_preserve_binding_mode_2024, "1.79.0", Some(123076)),
     /// Allows `mut ref` and `mut ref mut` identifier patterns.
     (incomplete, mut_ref, "1.79.0", Some(123076)),
     /// Allows using `#[naked]` on functions.
@@ -573,8 +571,6 @@ declare_features! (
     (unstable, raw_ref_op, "1.41.0", Some(64490)),
     /// Makes `&` and `&mut` patterns eat only one layer of references in Rust 2024.
     (incomplete, ref_pat_eat_one_layer_2024, "1.79.0", Some(123076)),
-    /// Allows `&` and `&mut` patterns to consume match-ergonomics-inserted references.
-    (incomplete, ref_pat_everywhere, "1.79.0", Some(123076)),
     /// Allows using the `#[register_tool]` attribute.
     (unstable, register_tool, "1.41.0", Some(66079)),
     /// Allows the `#[repr(i128)]` attribute for enums.