Problem: Variable name for 'messagesopt' doesn't match short name
(after v9.1.0908)
Solution: Change p_meo to p_mopt. Add more details to docs.
(zeertzjq)
closes: #16182
Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>