Document the new default_upn_domain attribute for LDAP servers (#1574)
Document the new default_upn_domain attribute for LDAP servers (#1574)

* document the new default_upn_domain attribute for LDAP servers

Signed-off-by: Justin Kolberg <ddf45d6578c36b76a30bc5f620c283d41c59bd42@gmail.com>

* move to ad section (#1583)

sensu/sensu-docs,sensu/sensu-docs,sensu/sensu-docs,sensu/sensu-docs,sensu/sensu-docs