Remove explicit interface versions of dartdoc files.

lib/html/doc/interface/ProcessingInstruction.dartdoc

Index: lib/html/doc/interface/ProcessingInstruction.dartdoc
diff --git a/lib/html/doc/interface/ProcessingInstruction.dartdoc b/lib/html/doc/interface/ProcessingInstruction.dartdoc
deleted file mode 100644
index 666cfb7f7e53fbd7a41a6ed9ad8cd41c0144f00e..0000000000000000000000000000000000000000
--- a/lib/html/doc/interface/ProcessingInstruction.dartdoc
+++ /dev/null
@@ -1,20 +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 ProcessingInstruction
-interface ProcessingInstruction extends Node {
-
-  /** @domName ProcessingInstruction.data */
-  String data;
-
-  /** @domName ProcessingInstruction.sheet */
-  final StyleSheet sheet;
-
-  /** @domName ProcessingInstruction.target */
-  final String target;
-}