Stdlib: reintroduce MBytes.pp_hex

src/lib_stdlib/mBytes.ml

@@ -27,3 +27,7 @@ let to_hex t =
 
 let of_hex hex =
   Cstruct.to_bigarray (Hex.to_cstruct hex)
+
+let pp_hex ppf s =
+  let `Hex hex = to_hex s in
+  Format.pp_print_string ppf hex

src/lib_stdlib/mBytes.mli

@@ -21,3 +21,4 @@ module LE : EndianBigstring.EndianBigstringSig
 val make : int -> char -> t
 val of_hex : Hex.t -> t
 val to_hex : t -> Hex.t
+val pp_hex : Format.formatter -> t -> unit