Remove explicit interface versions of dartdoc files.

lib/html/doc/interface/KeygenElement.dartdoc

Index: lib/html/doc/interface/KeygenElement.dartdoc
diff --git a/lib/html/doc/interface/KeygenElement.dartdoc b/lib/html/doc/interface/KeygenElement.dartdoc
deleted file mode 100644
index 7bfa5af7ae4a3d54204fe847395a75603a3cf51a..0000000000000000000000000000000000000000
--- a/lib/html/doc/interface/KeygenElement.dartdoc
+++ /dev/null
@@ -1,52 +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 HTMLKeygenElement
-interface KeygenElement extends Element default _Elements {
-
-  KeygenElement();
-
-  /** @domName HTMLKeygenElement.autofocus */
-  bool autofocus;
-
-  /** @domName HTMLKeygenElement.challenge */
-  String challenge;
-
-  /** @domName HTMLKeygenElement.disabled */
-  bool disabled;
-
-  /** @domName HTMLKeygenElement.form */
-  final FormElement form;
-
-  /** @domName HTMLKeygenElement.keytype */
-  String keytype;
-
-  /** @domName HTMLKeygenElement.labels */
-  final NodeList labels;
-
-  /** @domName HTMLKeygenElement.name */
-  String name;
-
-  /** @domName HTMLKeygenElement.type */
-  final String type;
-
-  /** @domName HTMLKeygenElement.validationMessage */
-  final String validationMessage;
-
-  /** @domName HTMLKeygenElement.validity */
-  final ValidityState validity;
-
-  /** @domName HTMLKeygenElement.willValidate */
-  final bool willValidate;
-
-  /** @domName HTMLKeygenElement.checkValidity */
-  bool checkValidity();
-
-  /** @domName HTMLKeygenElement.setCustomValidity */
-  void setCustomValidity(String error);
-}