sdpops: docs - note that second param of ki_sdp_get_line_startswith() can have pv

src/modules/sdpops/doc/sdpops_admin.xml

@@ -557,6 +557,7 @@ if(sdp_with_ice()) {
 		<para>
 			Store the search part of SDP body message with line beginning with 'string' in an AVP. 
 			Return 1 if 'string' is found in SDP, -1 on error and -2 if there is no SDP part in the message body.
+			The second parameter can contain psudeo-variables.
 		</para>
 		<para>
 			This function can be used from ANY_ROUTE.