Update tests/monoid_enriched_cat.v

Author: CohenCyril

tests/monoid_enriched_cat.v

@@ -45,6 +45,8 @@ HB.instance Definition _ (T : Monoid_enriched_quiver.type) (A B : T) : isMon (@h
 
   (* each instance of isMon should be tried as an instance of hom_isMon *)
 
+(* Step 3: for each instance of a wrapped mixin on a subject known 
+  to be wrapped, automatically produce an instance of the wrapper mixin too. *)
 HB.instance Definition _ := isQuiver.Build Type (fun A B => A -> B).
 Fail HB.instance Definition homTypeMon (A B : Quiver.type) := isMon.Build (hom A B) (* ... *).
 (* This last command should create a `Monoid_enriched_quiver`, in order to do so it should