Rename the FIXMEs, remove a few that dont matter anymore

compiler/rustc_trait_selection/src/traits/fulfill.rs

@@ -374,7 +374,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                 | ty::PredicateKind::Coerce(_)
                 | ty::PredicateKind::Clause(ty::ClauseKind::ConstEvaluatable(..))
                 | ty::PredicateKind::ConstEquate(..)
-                // FIXME(effects): We may need to do this using the higher-ranked
+                // FIXME(const_trait_impl): We may need to do this using the higher-ranked
                 // pred instead of just instantiating it with placeholders b/c of
                 // higher-ranked implied bound issues in the old solver.
                 | ty::PredicateKind::Clause(ty::ClauseKind::HostEffect(..)) => {

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

@@ -1170,8 +1170,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         _obligation: &PolyTraitObligation<'tcx>,
         candidates: &mut SelectionCandidateSet<'tcx>,
     ) {
-        // FIXME(effects): Destruct is not const yet, and it is implemented
-        // by all types today in non-const setting.
         candidates.vec.push(BuiltinCandidate { has_nested: false });
     }