Rollup merge of #110345 - nnethercote:rm-Super-impls-for-Region, r=compiler-errors

Remove `TypeSuper{Foldable,Visitable}` impls for `Region`.

These traits exist so that folders/visitors can recurse into types of interest: binders, types, regions, predicates, and consts. But `Region` is non-recursive and cannot contain other types of interest, so its methods in these traits are trivial.

This commit inlines and removes those trivial methods.

r? `@compiler-errors`

compiler/rustc_trait_selection/src/traits/mod.rs

@@ -450,7 +450,7 @@ fn is_impossible_method(tcx: TyCtxt<'_>, (impl_def_id, trait_item_def_id): (DefI
             {
                 return ControlFlow::Break(());
             }
-            r.super_visit_with(self)
+            ControlFlow::Continue(())
         }
         fn visit_const(&mut self, ct: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
             if let ty::ConstKind::Param(param) = ct.kind()