Revert "Merge #12357: nixos docs: show references to packages"

The PR wasn't good enough yet.
This reverts commit b2a37ceeea, reversing
changes made to 7fa9a1abce.

nixos/modules/services/misc/subsonic.nix

@@ -97,7 +97,6 @@ in
 
       transcoders = mkOption {
         type = types.listOf types.path;
-        default = [ "${pkgs.ffmpeg}/bin/ffmpeg" ];
         description = ''
           List of paths to transcoder executables that should be accessible
           from Subsonic. Symlinks will be created to each executable inside
@@ -153,5 +152,8 @@ in
     };
 
     users.extraGroups.subsonic.gid = config.ids.gids.subsonic;
+
+    services.subsonic.transcoders = mkDefault [ "${pkgs.ffmpeg}/bin/ffmpeg" ];
+
   };
 }