[Effen] typo fix: 'cusor' => 'cursor' in editable_text.dart

sky/framework/editing/editable_text.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import '../fn.dart';
 import '../theme/colors.dart';
 import 'dart:async';
 import 'editable_string.dart';
 
 class EditableText extends Component {
   static final Style _style = new Style('''
     display: inline;'''
   );
 
-  static final Style _cusorStyle = new Style('''
+  static final Style _cursorStyle = new Style('''
     display: inline-flex;
     width: 2px;
     height: 1.2em;
     vertical-align: top;
     background-color: ${Blue[500]};'''
   );
 
   static final Style _composingStyle = new Style('''
     display: inline;
     text-decoration: underline;'''
@@ skipping 53 matching lines @@
           children: [new Text(composing)]
         ));
       }
 
       String afterComposing = value.textAfter(value.composing);
       if (!afterComposing.isEmpty)
         children.add(new Text(afterComposing));
     }
 
     if (_showCursor)
-      children.add(new Container(key: 'cursor', style: _cusorStyle));
+      children.add(new Container(key: 'cursor', style: _cursorStyle));
 
     return new Container(
       style: _style,
       children: children
     );
   }
 }