nixos/hardware.nitrokey: update documentation

The nitrokey group has been removed in NixOS#108319.

Author: robinkrahl

nixos/modules/hardware/nitrokey.nix

@@ -11,9 +11,7 @@ in
       type = lib.types.bool;
       default = false;
       description = ''
-        Enables udev rules for Nitrokey devices. By default grants access
-        to users in the "nitrokey" group. You may want to install the
-        nitrokey-app package, depending on your device and needs.
+        Enables udev rules for Nitrokey devices.
       '';
     };
   };