anchor.diff:  ///                 ),
   ///               ),
   ///             ),
  -///             TextField(
  +///             const TextField(
   ///               maxLines: 2,
   ///               decoration: InputDecoration(
   ///                 hintText: 'Up/down behave normally here.',
  
positive.code: ///         child: Column(
  ///           mainAxisAlignment: MainAxisAlignment.center,
  ///           children: <Widget>[
  ///             Text(
  ///               'You have pushed the button this many times:',
  ///             ),
  ///             Text(
  
negative.code: ///                     },
  ///                   ),
  ///                 },
  ///                 child: const TextField(
  ///                   maxLines: 2,
  ///                   decoration: InputDecoration(
  ///                     hintText: 'Up/down increment/decrement here.',
  