Clarify presentation of the target in retaining paths.

runtime/observatory/lib/src/elements/error_view.dart

 // 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.
 
 library error_view_element;
 
 import 'dart:html';
 import 'dart:async';
 import 'package:observatory/models.dart' as M;
 import 'package:observatory/src/elements/helpers/nav_bar.dart';
@@ skipping 71 matching lines @@
     switch (kind) {
       case M.ErrorKind.unhandledException:
         return 'Unhandled Exception';
       case M.ErrorKind.languageError:
         return 'Language Error';
       case M.ErrorKind.internalError:
         return 'Internal Error';
       case M.ErrorKind.terminationError:
         return 'Termination Error';
     }
-    throw new Exception('Unkown M.ErrorKind ($kind)');
+    throw new Exception('Unknown M.ErrorKind ($kind)');
   }
 }