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

src/common/ParamX.gf

@@ -64,5 +64,11 @@ resource ParamX = open Prelude in {
   param
     DTail = T1 | T2 | T3 ;
 
+  oper
+    inc : DTail -> DTail = \t -> case t of {
+      T1 => T2 ;
+      T2 => T3 ;
+      T3 => T1
+      } ;
 
 }