Change all File APIs to make the mode and encoding arguments named

sdk/lib/_internal/dartdoc/lib/src/dartdoc/utils.dart

Index: sdk/lib/_internal/dartdoc/lib/src/dartdoc/utils.dart
diff --git a/sdk/lib/_internal/dartdoc/lib/src/dartdoc/utils.dart b/sdk/lib/_internal/dartdoc/lib/src/dartdoc/utils.dart
index e8cae413f8b5ff1bff6bfd706d5a89317456f9df..470c9f2046c7157189b4426b4631088717cce672 100644
--- a/sdk/lib/_internal/dartdoc/lib/src/dartdoc/utils.dart
+++ b/sdk/lib/_internal/dartdoc/lib/src/dartdoc/utils.dart
@@ -1,4 +1,4 @@
-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2013, 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.
 
@@ -73,7 +73,7 @@ String joinWithCommas(List<String> items, [String conjunction = 'and']) {
 }
 
 void writeString(File file, String text) {
-  var randomAccessFile = file.openSync(FileMode.WRITE);
+  var randomAccessFile = file.openSync(mode: FileMode.WRITE);
   randomAccessFile.writeStringSync(text);
   randomAccessFile.closeSync();
 }