tab method
Implementation
@override
void tab() {
final rightLimit = _horizontalTabRightLimit();
if (_buffer.cursorX >= rightLimit) return;
final nextStop = _tabStops.find(_buffer.cursorX + 1, rightLimit + 1);
if (nextStop != null) {
_buffer.setCursorX(nextStop);
} else {
_buffer.setCursorX(rightLimit);
}
}