anchor.diff:  /// {@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
  +/// This 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:
   ///
  
positive.code: ///
  /// {@tool sample}
  ///
  /// The following is a skeleton of a stateless widget subclass called `GreenFrog`:
  ///
  /// ```dart
  /// class GreenFrog extends StatelessWidget {
  
negative.code: ///
  /// {@tool sample}
  ///
  /// This is a skeleton of a stateful widget subclass called `YellowBird`.
  ///
  /// 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.
  ///
  /// ```dart
  /// class YellowBird extends StatefulWidget {
  