qapi/qdev: Tidy up device_add documentation

qapi/qdev: Tidy up device_add documentation

The notes section comes out like this:

    Notes

    Additional arguments depend on the type.

    1. For detailed information about this command, please refer to the
       ‘docs/qdev-device-use.txt’ file.

    2. It’s possible to list device properties by running QEMU with the
       “-device DEVICE,help” command-line argument, where DEVICE is the
       device’s name

The first item isn't numbered.  Fix that:

    1. Additional arguments depend on the type.

    2. For detailed information about this command, please refer to the
       ‘docs/qdev-device-use.txt’ file.

    3. It’s possible to list device properties by running QEMU with the
       “-device DEVICE,help” command-line argument, where DEVICE is the
       device’s name

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20230720071610.1096458-4-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>