nixos/users-groups: fix broken linger

    in stringAfter [ "users" ] ''

      if [ -e ${lingerDir} ] ; then

        cd ${lingerDir}

        for user in ${lingerDir}/*; do

          if ! id "$user" >/dev/null 2>&1; then

        for user in $(ls); do

          if ! id "$user" >/dev/null; then

            echo "Removing linger for deleted user $user"

            rm --force -- "$user"

          fi

        done