doc: mention default QEMU exit keybinding

Quitting directly is easier then first switching to the qemu console and
then entering `quit`.

https://www.qemu.org/docs/master/system/mux-chardev.html

diff --git a/mkosi/resources/mkosi.md b/mkosi/resources/mkosi.md
index c2bf5a4644355d442781c2fd85627a538f868105..23dc3b4d9090bc529bab262b0b47d274e363da7e 100644 (file)
--- a/mkosi/resources/mkosi.md
+++ b/mkosi/resources/mkosi.md
@@ -2536,7 +2536,8 @@ and later the getty login prompt and shell all use the same terminal.
 It is possible to switch between the qemu console and monitor
 by pressing `Ctrl-a c`.
 The qemu monitor may for example be used to inject special keys
-or shut down the machine quickly.
+or shut down the machine quickly. Alternatively the machine can be shut down
+using `Ctrl-a x`.
 
 To boot with a graphical window, add `--qemu-qui`:
 ```console