qemu-docs: Update options for graphical frontends

The command line options `-ctrl-grab` and `-alt-grab` have been removed
in QEMU 7.1. Instead, use the `-display sdl,grab-mod=<modifiers>` option
to specify the grab modifiers.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2103
Signed-off-by: Yihuan Pan <xun794@gmail.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
1 file changed