anchor.diff:    /// The default behavior varies from font to font.
     ///
     /// {@tool sample --template=stateless_widget}
  -  ///
     /// The Kufam font supports the `pnum` feature. It causes the digits
     /// to become proportionally-sized, rather than all being the same
     /// width. In this font this is especially noticeable with the digit
  
positive.code:   /// [FontFeature.liningFigures].
    ///
    /// {@tool sample --template=stateless_widget}
    ///
    /// The Piazzolla font supports the `onum` feature. It causes
    /// digits to extend below the baseline.
    ///
    /// ```dart dartImports
    /// import 'dart:ui';
    /// ```
    ///
    /// ```dart
    /// Widget build(BuildContext context) {
    ///   // The Piazzolla font can be downloaded from Google Fonts (https://www.google.com/fonts).
    ///   return const Text(
    ///     'Call 311-555-2368 now!',
    ///     style: TextStyle(
    ///       fontFamily: 'Piazzolla',
    ///       fontFeatures: <FontFeature>[
    ///         FontFeature.oldstyleFigures(),
    ///       ],
    ///     ),
    ///   );
    /// }
    /// ```
    ///
    /// ![](https://flutter.github.io/assets-for-api-docs/assets/dart-ui/font_feature_onum.png)
    /// {@end-tool}
    ///
    /// See also:
  
negative.code:   ///
    /// The code below shows how to select set 3.
    ///
    /// ![](https://flutter.github.io/assets-for-api-docs/assets/dart-ui/font_feature_nalt.png)
    ///
    /// ** See code in examples/api/lib/ui/text/font_feature.font_feature_notational_forms.0.dart **
    /// {@end-tool}
    ///
    /// See also:
  