docs/devel: Fix link to developer mailing lists

Ammends commit 9f73de8d 'docs: rSTify
the "SubmitAPatch" wiki'.

Cc: qemu-stable@nongnu.org
Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20220520180109.8224-11-shentey@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>