Auto merge of #127008 - Jules-Bertholet:tc-ergonomics, r=Nadrieril

Match ergonomics 2024: Implement TC's match ergonomics proposal

Under gate `ref_pat_eat_one_layer_2024_structural`. Enabling `ref_pat_eat_one_layer_2024` at the same time allows the union of what the individual gates allow. `@traviscross`

r? `@Nadrieril`

cc rust-lang/rust#123076

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

Author: bors