msgport.9: Add cross reference to sleep(9).

diff --git a/share/man/man9/msgport.9 b/share/man/man9/msgport.9
index 5d1ccb9..d112e27 100644 (file)
--- a/share/man/man9/msgport.9
+++ b/share/man/man9/msgport.9
@@ -587,7 +587,8 @@ When a message is replied to, the error response is written on the message
 which is subsequently sent to the reply port.
 .Sh SEE ALSO
 .Xr serializer 9 ,
-.Xr spinlock 9
+.Xr spinlock 9 ,
+.Xr sleep 9
 .Sh HISTORY
 The LWKT msgport interface first appeared in
 .Dx 1.0 .