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/libip6t_icmp6.c b/extensions/libip6t_icmp6.c
index caecc4f..c29fe61 100644
--- a/extensions/libip6t_icmp6.c
+++ b/extensions/libip6t_icmp6.c
@@ -78,7 +78,7 @@
 {
 	printf(
 "icmpv6 match options:\n"
-" --icmpv6-type [!] typename	match icmpv6 type\n"
+"[!] --icmpv6-type typename	match icmpv6 type\n"
 "				(or numeric type or type/code)\n");
 	print_icmpv6types();
 }