Clarified zmq_msg_close not needed after zmq_msg_send

doc/zmq_msg_close.txt

@@ -21,7 +21,8 @@ message object shall be postponed by 0MQ until all users of the message or
 underlying data buffer have indicated it is no longer required.
 
 Applications should ensure that _zmq_msg_close()_ is called once a message is
-no longer required, otherwise memory leaks may occur.
+no longer required, otherwise memory leaks may occur. Note that this is NOT
+necessary after a successful _zmq_msg_send()_.
 
 CAUTION: Never access 'zmq_msg_t' members directly, instead always use the
 _zmq_msg_ family of functions.

doc/zmq_msg_send.txt

@@ -38,7 +38,8 @@ it using (e.g. using _zmq_msg_copy()_).
 
 NOTE: A successful invocation of _zmq_msg_send()_ does not indicate that the
 message has been transmitted to the network, only that it has been queued on
-the 'socket' and 0MQ has assumed responsibility for the message.
+the 'socket' and 0MQ has assumed responsibility for the message. You do not need
+to call _zmq_msg_close()_ after a successful _zmq_msg_send()_.
 
 
 Multi-part messages