move NumeralX.inc to ParamX since it is used in many places

src/catalan/NumeralCat.gf

@@ -179,12 +179,6 @@ param
       _  => BIND
       } ;
 
-    inc : DTail -> DTail = \t -> case t of {
-      T1 => T2 ;
-      T2 => T3 ;
-      T3 => T1
-      } ;
-
   oper
     mk2Dig : Str -> Str -> TDigit = \c,o -> mk3Dig c o Pl ;
     mkDig : Str -> TDigit = \c -> mk2Dig c (c + ":o") ;