Remove explicit interface versions of dartdoc files.

lib/html/doc/interface/ElementTraversal.dartdoc

Index: lib/html/doc/interface/ElementTraversal.dartdoc
diff --git a/lib/html/doc/interface/ElementTraversal.dartdoc b/lib/html/doc/interface/ElementTraversal.dartdoc
deleted file mode 100644
index f06a821188767f6c82d99e456052689d38ccaff7..0000000000000000000000000000000000000000
--- a/lib/html/doc/interface/ElementTraversal.dartdoc
+++ /dev/null
@@ -1,26 +0,0 @@
-// 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 ElementTraversal
-interface ElementTraversal {
-
-  /** @domName ElementTraversal.childElementCount */
-  final int childElementCount;
-
-  /** @domName ElementTraversal.firstElementChild */
-  final Element firstElementChild;
-
-  /** @domName ElementTraversal.lastElementChild */
-  final Element lastElementChild;
-
-  /** @domName ElementTraversal.nextElementSibling */
-  final Element nextElementSibling;
-
-  /** @domName ElementTraversal.previousElementSibling */
-  final Element previousElementSibling;
-}