doc: rgw: document v6 endpoint options

document that v6 endpoints only binds to ipv6

Signed-off-by: Abhishek Lekshmanan <abhishek@suse.com>
(cherry picked from commit 59c7687)

doc/radosgw/frontends.rst

@@ -23,21 +23,21 @@ Options
 
 ``port`` and ``ssl_port``
 
-:Description: Sets the listening port number. Can be specified multiple
+:Description: Sets the ipv4 & ipv6 listening port number. Can be specified multiple
               times as in ``port=80 port=8000``.
-
 :Type: Integer
 :Default: ``80``
 
 
 ``endpoint`` and ``ssl_endpoint``
 
-:Description: Sets the listening address in the form ``address[:port]``,
-              where the address is an IPv4 address string in dotted decimal
-              form, or an IPv6 address in hexadecimal notation surrounded
-              by square brackets. The optional port defaults to 80 for
-              ``endpoint`` and 443 for ``ssl_endpoint``. Can be specified
-              multiple times as in ``endpoint=[::1] endpoint=192.168.0.100:8000``.
+:Description: Sets the listening address in the form ``address[:port]``, where
+              the address is an IPv4 address string in dotted decimal form, or
+              an IPv6 address in hexadecimal notation surrounded by square
+              brackets. Specifying a IPv6 endpoint would listen to v6 only. The
+              optional port defaults to 80 for ``endpoint`` and 443 for
+              ``ssl_endpoint``. Can be specified multiple times as in
+              ``endpoint=[::1] endpoint=192.168.0.100:8000``.
 
 :Type: Integer
 :Default: None