anchor.diff:  
       // _getLineBoundary only considers the offset and assumes that the
       // TextAffinity is upstream. In the case that TextPosition is just after a
  -    // wordwrap (downstream), we need to return the line for the next offset.
  +    // word wrap (downstream), we need to return the line for the next offset.
       if (position.affinity == TextAffinity.downstream && line != nextLine
           && position.offset == line.end && line.end == nextLine.start) {
         final List<int> nextBoundary = _getLineBoundary(position.offset + 1);
  
positive.code:   ///
    /// This is overridden by [FontFeature.oldstyleFigures].
    ///
    /// {@tool sample --template=stateless_widget}
    /// The Source Code Pro font supports the `zero` feature. It causes the
    /// zero digit to be drawn with a slash rather than the default rendering,
    /// which in this case has a dot through the zero rather than a slash.
  
negative.code:   ///
    /// This feature may override other glyph-substitution features.
    ///
    /// {@tool sample}
    /// The Cardo font supports the `hlig` feature. It has legacy
    /// ligatures for "VI" and "NT", and various ligatures involving the
    /// "long s". In the example below, both historical forms (`hist 1`)
  