add comment warning about hardcoded smith metadata

pallets/membership/src/benchmarking.rs

@@ -44,6 +44,9 @@ benchmarks_instance_pallet! {
         assert_has_event::<T, I>(Event::<T, I>::MembershipRequested(idty).into());
     }
     request_membership {
+        // Dave identity (4)
+        // for main wot, no constraints
+        // for smith subwot, his pubkey is hardcoded in default metadata
         let idty: T::IdtyId = 4.into();
         Membership::<T, I>::take(idty);
         let caller: T::AccountId = T::AccountIdOf::convert(idty.clone()).unwrap();