fix: strong type aliases in Random (closes #210)

src/core/CCChar.mli

@@ -4,7 +4,7 @@
 
     @since 0.14 *)
 
-include module type of Char
+include module type of struct include Char end
 
 val equal : t -> t -> bool
 (** The equal function for chars. *)

src/core/CCRandom.mli

@@ -3,7 +3,7 @@
 
 (** {1 Random Generators} *)
 
-include module type of Random
+include module type of struct include Random end
 
 type state = Random.State.t
 

src/core/CCResult.mli

@@ -14,7 +14,7 @@ type 'a printer = Format.formatter -> 'a -> unit
 
 (** {2 Basics} *)
 
-include module type of Result
+include module type of struct include Result end
 (** @since 1.5 *)
 
 type (+'good, +'bad) t = ('good, 'bad) Result.result =

src/core/CCString.mli

@@ -60,7 +60,7 @@ end
 
 (** {2 Strings} *)
 
-include module type of String
+include module type of struct include String end
 
 val equal : string -> string -> bool
 (** Equality function on strings. *)