multi_socket_action: clarify how to kickstart it

The callbacks are called when curl_multi_socket_action() is called, not
when handles are added. This is now mentioned in the "TYPICAL USAGE"
section.

docs/libcurl/curl_multi_socket_action.3

@@ -112,14 +112,15 @@ timeout value to use when waiting for socket activities.
 them for activity. This can be done through your application code, or by way
 of an external library such as libevent or glib.
 
-6. Wait for activity on any of libcurl's sockets, use the timeout value your
+6. Call curl_multi_socket_action() to kickstart everything. To get one or more
+callbacks called.
+
+7. Wait for activity on any of libcurl's sockets, use the timeout value your
 callback has been told
 
-7, When activity is detected, call curl_multi_socket_action() for the
+8, When activity is detected, call curl_multi_socket_action() for the
 socket(s) that got action. If no activity is detected and the timeout expires,
 call \fIcurl_multi_socket_action(3)\fP with \fICURL_SOCKET_TIMEOUT\fP
-
-8. Go back to step 6.
 .SH AVAILABILITY
 This function was added in libcurl 7.15.4, and is deemed stable since 7.16.0.
 .SH "SEE ALSO"