[javascript-hint addon] Properly iterate over local scopes

See https://discuss.codemirror.net/t/function-parameter-autocomplete/2240/1

Author: marijnh

addon/hint/javascript-hint.js

@@ -147,6 +147,8 @@
       // If not, just look in the global object and any local scope
       // (reading into JS mode internals to get at the local and global variables)
       for (var v = token.state.localVars; v; v = v.next) maybeAdd(v.name);
+      for (var c = token.state.context; c; c = c.prev)
+        for (var v = c.vars; v; v = v.next) maybeAdd(v.name)
       for (var v = token.state.globalVars; v; v = v.next) maybeAdd(v.name);
       if (!options || options.useGlobalScope !== false)
         gatherCompletions(global);