Original config from a documentation causes an error with keyboard-layout function

[Adam Mazurkiewicz <trzczy@gmail.com>]

I am a newbie and I am learning installing Guixsd step by step. I have
surprised that using a config file from a documentation generates the
error. Actually I am not sure if I am doing mistakes or the documentation
is wrong. I used the config file from a site:

https://www.gnu.org/software/guix/manual/en/html_node/Using-the-Configuration-System.html#Using-the-Configuration-System

The config file I used was this

----config.scm-----
(use-modules (gnu) (gnu system nss))
(use-service-modules desktop xorg)
(use-package-modules certs gnome)

(operating-system
  (host-name "antelope")
  (timezone "Europe/Paris")
  (locale "en_US.utf8")

  ;; Choose US English keyboard layout.  The "altgr-intl"
  ;; variant provides dead keys for accented characters.
  (keyboard-layout (keyboard-layout "us" "altgr-intl"))

  ;; Use the UEFI variant of GRUB with the EFI System
  ;; Partition mounted on /boot/efi.
  (bootloader (bootloader-configuration
                (bootloader grub-efi-bootloader)
                (target "/boot/efi")
                (keyboard-layout keyboard-layout)))

  ;; Specify a mapped device for the encrypted root partition.
  ;; The UUID is that returned by 'cryptsetup luksUUID'.
  (mapped-devices
   (list (mapped-device
          (source (uuid "12345678-1234-1234-1234-123456789abc"))
          (target "my-root")
          (type luks-device-mapping))))

  (file-systems (append
                 (list (file-system
                         (device (file-system-label "my-root"))
                         (mount-point "/")
                         (type "ext4")
                         (dependencies mapped-devices))
                       (file-system
                         (device (uuid "1234-ABCD" 'fat))
                         (mount-point "/boot/efi")
                         (type "vfat")))
                 %base-file-systems))

  (users (cons (user-account
                (name "bob")
                (comment "Alice's brother")
                (group "users")
                (supplementary-groups '("wheel" "netdev"
                                        "audio" "video")))
               %base-user-accounts))

  ;; This is where we specify system-wide packages.
  (packages (append (list
                     ;; for HTTPS access
                     nss-certs
                     ;; for user mounts
                     gvfs)
                    %base-packages))

  ;; Add GNOME and Xfce---we can choose at the log-in screen
  ;; by clicking the gear.  Use the "desktop" services, which
  ;; include the X11 log-in service, networking with
  ;; NetworkManager, and more.
  (services (append (list (service gnome-desktop-service-type)
                          (service xfce-desktop-service-type)
                          (set-xorg-configuration
                           (xorg-configuration
                            (keyboard-layout keyboard-layout))))
                    %desktop-services))

  ;; Allow resolution of '.local' host names with mDNS.
  (name-service-switch %mdns-host-lookup-nss))
----config.scm---end--

Using this file caused the error:
/root/sda6/home/s/Dropbox/Guix/scm1/config.scm:5:0: error: extraneous field
initializers (keyboard-layout)

So it is something wrong with the keyboard-layout function. The function is
used a few times so we do not know which one actually causes the error.

Is this the documentation mistake or I am doing something wrong? How to use
the function keyboard-layout properly?