Move to Another Monitor options not localizable

Options like "Monitor Left" are not localizable. The strings are not on Transifex.

Looks like the strings are not marked with N_:

https://gitlab.xfce.org/xfce/xfwm4/-/blob/0b9f39ba2a64832692479254c2c58ef9dd8f0997/src/menu.c#L200-219