func ToTitle(s []byte) []byte { return Map(unicode.ToTitle, s) }

// ToUpperSpecial treats s as UTF-8-encoded bytes and returns a copy with all the Unicode letters mapped to their
// upper case, giving priority to the special casing rules.
func ToUpperSpecial(c unicode.SpecialCase, s []byte) []byte {
	return Map(c.ToUpper, s)
}