ammonite: fix #68151

Upstream doesn't include a shebang line but recommends adding one at
installation time. NixOS users noticed that the command wouldn't exec
when using certain shells.

pkgs/development/tools/ammonite/default.nix

@@ -22,6 +22,7 @@ stdenv.mkDerivation rec {
     sed -i '0,/java/{s|java|${jre}/bin/java|}' $out/bin/amm
   '' + optionalString (disableRemoteLogging) ''
     sed -i '0,/ammonite.Main/{s|ammonite.Main|ammonite.Main --no-remote-logging|}' $out/bin/amm
+    sed -i '1i #!/bin/sh' $out/bin/amm
   '';
 
   meta = {