multi calls for democracy.votes and staking.controllers (#887)

* .multi for democracy.votes & stating.controllers

* Removed leftover comment from https://github.com/polkadot-js/api/pull/875

* no new line at the end

packages/api-derive/src/staking/controllers.ts

@@ -11,10 +11,7 @@ import { drr } from '../util/drr';
 
 function allBonds (api: ApiInterface$Rx, stashIds: Array<AccountId>) {
   return combineLatest(
-    // FIXME Convert to multi
-    stashIds.map((id) =>
-      (api.query.staking.bonded(id) as Observable<Option<AccountId>>)
-    )
+    api.query.staking.bonded.multi(stashIds) as Observable<Option<AccountId>>
   );
 }