Improve nn_term and nn_shutdown manpages

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
diff --git a/doc/nn_shutdown.txt b/doc/nn_shutdown.txt
index 789f596..95dade4 100644
--- a/doc/nn_shutdown.txt
+++ b/doc/nn_shutdown.txt
@@ -17,9 +17,9 @@
 -----------
 Removes an endpoint from socket 's'. 'how' parameter specifies the ID of the
 endpoint to remove as returned by prior call to linknanomsg:nn_bind[3] or
-linknanomsg:nn_connect[3]. The library will try to deliver any outstanding
-outbound messages to this endpoint for the time specified by _NN_LINGER_ socket
-option. The call will block in the meantime.
+linknanomsg:nn_connect[3]. _nn_shutdown()_ call will return immediately,
+however, the library will try to deliver any outstanding outbound messages to
+the endpoint for the time specified by _NN_LINGER_ socket option.
 
 
 RETURN VALUE
diff --git a/doc/nn_term.txt b/doc/nn_term.txt
index 16df637..27aca1a 100644
--- a/doc/nn_term.txt
+++ b/doc/nn_term.txt
@@ -29,6 +29,8 @@
 _poll()_ or _select()_, the call will unblock with both _NN_SNDFD_ and
 _NN_RCVFD_ signaled.
 
+The _nn_term()_ function itself is non-blocking.
+
 
 EXAMPLE
 -------