complexQuantityToTex function
A complex quantity: brackets around both parts before the unit.
Implementation
String complexQuantityToTex(
String number,
String unit, {
SiOptions options = const SiOptions(),
}) {
final o = options._forUnit(unit);
final u = _unitToTex(unit, o, 1);
final c = _parseComplex(number, o);
if (c == null) return quantityToTex(number, unit, options: options);
final (tex, both) = _formatComplex(c, o);
return _quantityParts(both ? '($tex)' : tex, unit, u, o);
}