python pycangjie: add python.libPrefix

pkgs/development/python-modules/pycangjie/default.nix

···
 }:
 
 stdenv.mkDerivation rec {
-  name = "pycangjie-${version}";
+  name = "${python.libPrefix}-pycangjie-${version}";
   version = "1.3_rev_${rev}";
   rev = "361bb413203fd43bab624d98edf6f7d20ce6bfd3";