Mark dart:mirrors as having a (slightly) unstable API in the documentation.

sdk/lib/mirrors/mirrors.dart

Index: sdk/lib/mirrors/mirrors.dart
diff --git a/sdk/lib/mirrors/mirrors.dart b/sdk/lib/mirrors/mirrors.dart
index 10639522becc3ad14a2610ebb943d5ac225139e2..c6205a9de9c27a03b8504c3f3ae8d1daeaa6df9b 100644
--- a/sdk/lib/mirrors/mirrors.dart
+++ b/sdk/lib/mirrors/mirrors.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.
 
@@ -45,6 +45,14 @@
  * num, bool, String, a list of objects that are serializable
  * across isolates, or a map with keys and values that are all serializable across
  * isolates.
+ *
+ * ## Status: Unstable
+ *
+ * The dart:mirrors library is considered unstable and its API might
+ * change slightly as a result of feedback from users. There are two
+ * implementations of the library -- one for the native Dart VM and one
+ * for dart2js -- and they are both under development and may not
+ * support all operations yet.

[bakster, 2013/11/08 10:32:33]

- Remove "considered".
- use "user feedback".
- This library is platform dependent and it therefore has implementations for
both dart2js and the Dart VM. 
 
"not support all operations yet"  does not  match the lack of user feedback.
You might want to restate the last part.

  */
 library dart.mirrors;
 
@@ -568,7 +576,7 @@ abstract class LibraryMirror implements DeclarationMirror, ObjectMirror {
    * Returns a map of the top-level methods, getters and setters of the library.
    *
    * The intent is to capture those members that constitute the API of a
-   * library. Hence fields are not included, but the getters and setters 
+   * library. Hence fields are not included, but the getters and setters
    * implicitly introduced by fields are included. Synthetic getters for the
    * types exported by the library are also included.
    *