gitignore: Ignore generated ip6tables man pages

Fixes: 127eadee563e4 ("Makefile: Generate ip6tables man pages on the fly")
Signed-off-by: Phil Sutter <phil@nwl.cc>
diff --git a/iptables/.gitignore b/iptables/.gitignore
index cd7d87b..245e124 100644
--- a/iptables/.gitignore
+++ b/iptables/.gitignore
@@ -1,6 +1,10 @@
 /ip6tables
+/ip6tables.8
+/ip6tables-apply.8
 /ip6tables-save
+/ip6tables-save.8
 /ip6tables-restore
+/ip6tables-restore.8
 /ip6tables-static
 /ip6tables-translate.8
 /ip6tables-restore-translate.8