anchor.diff:  /// }
   /// ```
   /// {@end-tool}
  +///
   /// {@tool sample}
   ///
  -/// Normally widgets have more constructor arguments, each of which corresponds
  -/// to a `final` property. The next example shows the more generic widget `Frog`
  -/// which can be given a color and a child:
  +/// This next example shows the more generic widget `Frog` which can be given
  +/// a color and a child:
   ///
   /// ```dart
   /// class Frog extends StatelessWidget {
   ///   const Frog({
   ///     Key key,
  -///     this.color: const Color(0xFF2DBD3A),
  +///     this.color = const Color(0xFF2DBD3A),
   ///     this.child,
   ///   }) : super(key: key);
   ///
   ///   final Color color;
  -///
   ///   final Widget child;
   ///
   ///   @override
  
positive.code: /// {@end-tool}
  /// {@tool sample}
  ///
  /// In this example. the [State] has no actual state. State is normally
  /// represented as private member fields. Also, normally widgets have more
  /// constructor arguments, each of which corresponds to a `final` property.
  ///
  /// The next example shows the more generic widget `Bird` which can be given a
  /// color and a child, and which has some internal state with a method that
  /// can be called to mutate it:
  ///
  
negative.code: ///
  /// {@tool sample}
  ///
  /// The following is a skeleton of a stateless widget subclass called `GreenFrog`.
  ///
  /// Normally, widgets have more constructor arguments, each of which corresponds
  /// to a `final` property.
  ///
  /// ```dart
  /// class GreenFrog extends StatelessWidget {
  