Remove explicit interface versions of dartdoc files.

lib/html/doc/interface/SVGRadialGradientElement.dartdoc

Index: lib/html/doc/interface/SVGRadialGradientElement.dartdoc
diff --git a/lib/html/doc/interface/SVGRadialGradientElement.dartdoc b/lib/html/doc/interface/SVGRadialGradientElement.dartdoc
deleted file mode 100644
index 9e77650e9194529fb21c2cf385def769758c3ea9..0000000000000000000000000000000000000000
--- a/lib/html/doc/interface/SVGRadialGradientElement.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 SVGRadialGradientElement
-interface SVGRadialGradientElement extends SVGGradientElement {
-
-  /** @domName SVGRadialGradientElement.cx */
-  final SVGAnimatedLength cx;
-
-  /** @domName SVGRadialGradientElement.cy */
-  final SVGAnimatedLength cy;
-
-  /** @domName SVGRadialGradientElement.fx */
-  final SVGAnimatedLength fx;
-
-  /** @domName SVGRadialGradientElement.fy */
-  final SVGAnimatedLength fy;
-
-  /** @domName SVGRadialGradientElement.r */
-  final SVGAnimatedLength r;
-}