db_redis: docs - refine docs regarding client certificates [skip ci]

The created ssl context does not use client certificates [1,2] which is against the default in current Redis configurations [3]. The used Redis server therefore needs to be configured to not use tls-auth-clients [3].

There is also a small typo in "ac_path" which was fixed to "ca_path".

[1]: https://github.com/kamailio/kamailio/blob/8047c958b42ea5af2e8f9ede0152f892ac0eea3a/src/modules/db_redis/redis_connection.c#L168
[2]: https://github.com/kamailio/kamailio/blob/8047c958b42ea5af2e8f9ede0152f892ac0eea3a/src/modules/db_redis/redis_connection.c#L212
[3]: https://redis.io/docs/management/security/encryption/#client-certificate-authentication

src/modules/db_redis/doc/db_redis_admin.xml

@@ -224,6 +224,12 @@ modparam("db_redis", "verbosity", 0)
 				Controls TLS usage while connecting to a remote DB.
 				If set to 1, TLS is used to connect to the DB.
 			</para>
+			<para>
+				If TLS is enabled, the module will validate the Redis server certificate against the
+				ca_path. There is currently no way to connect with a specified client certificate, the
+				<ulink url="https://redis.io/docs/management/security/encryption/#client-certificate-authentication">corresponding configuration</ulink>
+				to check client certificates in the Redis server must therefore be turned off.
+			</para>
 			<para>
 				Default value: 0.
 			</para>
@@ -256,9 +262,9 @@ modparam("db_redis", "db_pass", "r3d1sPass")
 		</section>
 
 		<section id="db_redis.p.ca_path">
-			<title><varname>ac_path</varname> (string)</title>
+			<title><varname>ca_path</varname> (string)</title>
 			<para>
-				Sets the path where Certificates Authorities certs are stored.
+				Sets the path where Certificates Authorities certs for the Redis server certificate are stored.
 			</para>
 			<para>
 				Default value: "" (empty).