convert method
Implementation
@override
String convert() {
final root = _root;
final rootName = root.name;
final lines = <String>['#compdef $rootName', ''];
_writeCommand(lines, root, [rootName], const [], const []);
lines.add('compdef _${_pathIdentifier([rootName])} $rootName');
return '${lines.join('\n')}\n';
}