helix: fix wrapping of extraPackages

This makes extraPackages the default, but they do not shadow the env
so you can still have packages (e.g. LSPs) with a different version
than the global one in you local env like nix's shells.

modules/programs/helix.nix

@@ -188,7 +188,7 @@ in {
           nativeBuildInputs = [ pkgs.makeWrapper ];
           postBuild = ''
             wrapProgram $out/bin/hx \
-              --prefix PATH : ${lib.makeBinPath cfg.extraPackages}
+              --suffix PATH : ${lib.makeBinPath cfg.extraPackages}
           '';
         })
       ]