Remove explicit interface versions of dartdoc files.

lib/html/doc/interface/NodeIterator.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 NodeIterator
-interface NodeIterator {
-
-  /** @domName NodeIterator.expandEntityReferences */
-  final bool expandEntityReferences;
-
-  /** @domName NodeIterator.filter */
-  final NodeFilter filter;
-
-  /** @domName NodeIterator.pointerBeforeReferenceNode */
-  final bool pointerBeforeReferenceNode;
-
-  /** @domName NodeIterator.referenceNode */
-  final Node referenceNode;
-
-  /** @domName NodeIterator.root */
-  final Node root;
-
-  /** @domName NodeIterator.whatToShow */
-  final int whatToShow;
-
-  /** @domName NodeIterator.detach */
-  void detach();
-
-  /** @domName NodeIterator.nextNode */
-  Node nextNode();
-
-  /** @domName NodeIterator.previousNode */
-  Node previousNode();
-}