minor tcpdump.8 inconsistency

[Tim Kuijsten]

minor inconsistency

diff --git a/tcpdump.8 b/tcpdump.8
index ce16951..8c2cf33 100644
--- a/tcpdump.8
+++ b/tcpdump.8
@@ -1257,7 +1257,7 @@ end of this connection.
 .Ar window
 is the number of bytes of receive buffer space available
 at the other end of this connection.
-.Ar urg
+.Ar urgent
 indicates there is urgent data in the packet.
 .Ar options
 are TCP options enclosed in angle brackets e.g.,