Rollup merge of #133746 - oli-obk:push-xwyrylxmrtvq, r=jieyouxu

Change `AttrArgs::Eq` to a struct variant

Cleanups for simplifying rust-lang/rust#131808

Basically changes `AttrArgs::Eq` to a struct variant and then avoids several matches on `AttrArgsEq` in favor of methods on it. This will make future refactorings simpler, as they can either keep methods or switch to field accesses without having to restructure code

Author: GuillaumeGomez