Adds missing explanations about FIN in mask part of '--syn' in libip[6]_tcp.c
and libip6t_tcp.man.
diff --git a/extensions/libipt_tcp.c b/extensions/libipt_tcp.c
index c712b92..412b6cf 100644
--- a/extensions/libipt_tcp.c
+++ b/extensions/libipt_tcp.c
@@ -16,7 +16,7 @@
" --tcp-flags [!] mask comp match when TCP flags & mask == comp\n"
" (Flags: SYN ACK FIN RST URG PSH ALL NONE)\n"
"[!] --syn match when only SYN flag set\n"
-" (equivalent to --tcp-flags SYN,RST,ACK SYN)\n"
+" (equivalent to --tcp-flags SYN,RST,ACK,FIN SYN)\n"
" --source-port [!] port[:port]\n"
" --sport ...\n"
" match source port(s)\n"