Remove explicit interface versions of dartdoc files.

lib/html/doc/interface/TouchEvent.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 TouchEvent
-interface TouchEvent extends UIEvent {
-
-  /** @domName TouchEvent.altKey */
-  final bool altKey;
-
-  /** @domName TouchEvent.changedTouches */
-  final TouchList changedTouches;
-
-  /** @domName TouchEvent.ctrlKey */
-  final bool ctrlKey;
-
-  /** @domName TouchEvent.metaKey */
-  final bool metaKey;
-
-  /** @domName TouchEvent.shiftKey */
-  final bool shiftKey;
-
-  /** @domName TouchEvent.targetTouches */
-  final TouchList targetTouches;
-
-  /** @domName TouchEvent.touches */
-  final TouchList touches;
-
-  /** @domName TouchEvent.initTouchEvent */
-  void initTouchEvent(TouchList touches, TouchList targetTouches, TouchList changedTouches, String type, Window view, int screenX, int screenY, int clientX, int clientY, bool ctrlKey, bool altKey, bool shiftKey, bool metaKey);
-}