made comment into link

globals.mli

@@ -1,5 +1,5 @@
 (** Global variables with runtime (input-based) values, used in multiple
     modules. *)
 
-(** Values of command-line arguments, to be set by the [Main] module. *)
+(** Values of command-line arguments, to be set by the {!Main} module. *)
 val args : Types.args_record