Auto merge of #143879 - fee1-dead-contrib:push-lrlpoouyqqry, r=fmease

parse `const trait Trait`

r? oli-obk or anyone from project-const-traits

cc `@rust-lang/project-const-traits`

compiler/rustc_attr_parsing/src/attributes/traits.rs

@@ -91,6 +91,7 @@ impl<S: Stage> NoArgsAttributeParser<S> for DoNotImplementViaObjectParser {
     const CREATE: fn(Span) -> AttributeKind = AttributeKind::DoNotImplementViaObject;
 }
 
+// FIXME(const_trait_impl): remove this
 // Const traits
 
 pub(crate) struct ConstTraitParser;