De aqui :
To apply new [keyboard] settings, restarting the keyboard-setup service should suffice, otherwise you can try to restart kernel input system via udev:
udevadm trigger --subsystem-match=input --action=change
Para completar, reiniciar o keyboard-setup
seria parecido com
# For Ubuntu < 16.04
service keyboard-setup restart
# For Ubuntu >= 16.04
systemctl restart keyboard-setup