tuned module name space for generated code

--- a/src/HOL/Parity.thy	Thu May 21 22:06:15 2020 +0200
+++ b/src/HOL/Parity.thy	Thu May 21 20:00:08 2020 +0000
@@ -1668,4 +1668,7 @@
   \<open>drop_bit n k < 0 \<longleftrightarrow> k < 0\<close> for k :: int
   by (subst Not_eq_iff [symmetric]) (simp add: not_less)
 
+code_identifier
+  code_module Parity \<rightharpoonup> (SML) Arith and (OCaml) Arith and (Haskell) Arith
+
 end