tooltipFor method
tooltip as it reads on platform; off macOS the modifiers are
named control and shift (spec 14d L4: Strg in German).
Implementation
String tooltipFor(TargetPlatform platform,
{String control = 'Ctrl', String shift = 'Shift'}) {
if (shortcuts.isEmpty) return label;
final chord = shortcuts.first;
final key = chord.trigger.keyLabel;
final glyph = platform == TargetPlatform.macOS
? '⌘${chord.shift ? '⇧' : ''}$key'
: '$control+${chord.shift ? '$shift+' : ''}$key';
return '$label ($glyph)';
}