Synchronize invert flag order with manpages

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/extensions/libipt_icmp.c b/extensions/libipt_icmp.c
index 4361f13..f57503a 100644
--- a/extensions/libipt_icmp.c
+++ b/extensions/libipt_icmp.c
@@ -102,7 +102,7 @@
 {
 	printf(
 "icmp match options:\n"
-" --icmp-type [!] typename	match icmp type\n"
+"[!] --icmp-type typename	match icmp type\n"
 "				(or numeric type or type/code)\n");
 	print_icmptypes();
 }