Revert "Auto merge of #127537 - veluca93:struct_tf, r=BoxyUwU"

This reverts commit acb4e8b625, reversing
changes made to 100fde5246.

compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs

@@ -546,8 +546,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             // Provide an impl for suitable functions, rejecting `#[target_feature]` functions (RFC 2396).
             ty::FnDef(def_id, args) => {
                 let tcx = self.tcx();
-                // FIXME(struct_target_features): should a function that inherits target_features
-                // through an argument implement Fn traits?
                 if tcx.fn_sig(def_id).skip_binder().is_fn_trait_compatible()
                     && tcx.codegen_fn_attrs(def_id).target_features.is_empty()
                 {