changedLine method
What screen readers announce before an added or removed line.
number is its line number in the new or the old file.
Implementation
String changedLine(DiffLineKind kind, int? number) => switch (kind) {
DiffLineKind.added => 'Added line $number',
DiffLineKind.removed => 'Removed line $number',
DiffLineKind.context => 'Line $number',
};