Add missing newline at the end of options list

In qemu-kvm this place looks even more "interesting":

 -runas user     Change to user id user just before starting the VM.
 -readconfig <file>
 -writeconfig <file>
                read/write config file-no-kvm         disable KVM hardware virtualization
 -no-kvm-irqchip disable KVM kernel mode PIC/IOAPIC/LAPIC
 -no-kvm-pit     disable KVM kernel mode PIT
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

qemu-options.hx

@@ -1936,4 +1936,4 @@ DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
     "-readconfig <file>\n")
 DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig,
     "-writeconfig <file>\n"
-    "                read/write config file")
+    "                read/write config file\n")