rangeToTex function
A range: 1 to 10 (siunitx's default phrase).
Implementation
String rangeToTex(String a, String b, {String? unit, SiOptions? options}) {
final o = options ?? const SiOptions();
String side(String n) =>
unit == null ? numToTex(n) : quantityToTex(n, unit, options: o);
return '${side(a)}\\text{ to }${side(b)}';
}