Remove explicit interface versions of dartdoc files.

lib/html/doc/interface/StorageEvent.dartdoc

-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// WARNING:
-//   This file contains documentation that is merged into the real source.
-//   Do not make code changes here.
-
-/// @domName StorageEvent
-interface StorageEvent extends Event {
-
-  /** @domName StorageEvent.key */
-  final String key;
-
-  /** @domName StorageEvent.newValue */
-  final String newValue;
-
-  /** @domName StorageEvent.oldValue */
-  final String oldValue;
-
-  /** @domName StorageEvent.storageArea */
-  final Storage storageArea;
-
-  /** @domName StorageEvent.url */
-  final String url;
-
-  /** @domName StorageEvent.initStorageEvent */
-  void initStorageEvent(String typeArg, bool canBubbleArg, bool cancelableArg, String keyArg, String oldValueArg, String newValueArg, String urlArg, Storage storageAreaArg);
-}