changed comment only;

--- a/src/Pure/logic.ML	Fri Jul 01 11:10:31 1994 +0200
+++ b/src/Pure/logic.ML	Wed Jul 06 11:36:00 1994 +0200
@@ -141,7 +141,7 @@
 fun dest_type (Const ("TYPE", Type ("itself", [ty]))) = ty
   | dest_type t = raise TERM ("dest_type", [t]);
 
-(* class constraints: (| ty : c_class |) *)
+(** class constraints **)
 
 fun mk_inclass (ty, c) =
   Const (Sign.const_of_class c, itselfT ty --> propT) $ mk_type ty;