Case mappings
val to_lower : Stdlib.Uchar.t -> [ `Self | `Uchars of Stdlib.Uchar.t list ]to_lower u is u's Lowercase_Mapping property.
val to_upper : Stdlib.Uchar.t -> [ `Self | `Uchars of Stdlib.Uchar.t list ]to_upper u is u's Uppercase_Mapping property.
val to_title : Stdlib.Uchar.t -> [ `Self | `Uchars of Stdlib.Uchar.t list ]to_title u is u's Titlecase_Mapping property.