Removed inaccurate note in zmq_poll man page

doc/zmq_poll.txt

@@ -73,10 +73,6 @@ NOTE: The _zmq_poll()_ function may be implemented or emulated using operating
 system interfaces other than _poll()_, and as such may be subject to the limits
 of those interfaces in ways not defined in this documentation.
 
-NOTE: The _zmq_send()_ function will clear all pending events on a socket. Thus,
-if you use _zmq_poll()_ to monitor input on a socket, use it before output as
-well, and process all events after each _zmq_poll()_ call.
-
 RETURN VALUE
 ------------
 Upon successful completion, the _zmq_poll()_ function shall return the number