Fix Fn key for Keychron K2 in Linux

To temporary fix it, try

echo 0 | sudo tee /sys/module/hid_apple/parameters/fnmode

or

echo 1 | sudo tee /sys/module/hid_apple/parameters/fnmode

To apply changes permanently, do

echo "options hid_apple fnmode=0" | sudo tee -a /etc/modprobe.d/hid_apple.conf ;