registrar: fix docs remove_ip_port example

Author: razvancrainea

modules/registrar/doc/registrar_admin.xml

@@ -795,10 +795,10 @@ remove("location", "sip:[email protected]", , , "<urn:uuid:e5e68d40-f08a-4600-b
 		<programlisting format="linespecific">
 ...
 # remove all contacts behind 8.8.8.8 port 43213
-remove("8.8.8.8",43213,"location");
+remove_ip_port("8.8.8.8",43213,"location");
 ...
 # remove only bob's contacts behind the 8.8.8.8:43213 host
-remove("8.8.8.8",43213,"location","sip:[email protected]");
+remove_ip_port("8.8.8.8",43213,"location","sip:[email protected]");
 ...
 </programlisting>
 		</example>