d/iptables.postinst: include new alternatives for {arp,eb}tables

The nft version of them now include -restore and -save as well.

While at it, refresh README mentioning this.
Signed-off-by: Arturo Borrero Gonzalez <arturo@debian.org>

debian/README.Debian

@@ -19,7 +19,8 @@ following 2 basic approaches:
  * syntax reuse with nf_tables backend
    (iptables-nft, iptables-nft-restore, iptables-nft-save,
    ip6tables-nft, ip6tables-nft-restore, ip6tables-nft-save,
-   arptables-nft, ebtables-nft)
+   arptables-nft, arptables-nft-save, arptables-nft-restore,
+   ebtables-nft, ebtables-nft-save, ebtables-nft-restore)
 
 Documentation on how to use these tools can be found at:
 
@@ -52,7 +53,11 @@ kernel subsystem) are installed as:
  * /usr/sbin/ip6tables-nft-restore
  * /usr/sbin/ip6tables-nft-save
  * /usr/sbin/arptables-nft
+ * /usr/sbin/arptables-nft-restore
+ * /usr/sbin/arptables-nft-save
  * /usr/sbin/ebtables-nft
+ * /usr/sbin/ebtables-nft-restore
+ * /usr/sbin/ebtables-nft-save
 
 The iptables Debian package install both and gives the nft version more
 priority by default in the update-alternatives system. This means that if you

debian/iptables.postinst

@@ -20,9 +20,13 @@ if [ "$1" = "configure" ] || [ "$1" = "abort-upgrade" ]; then
           --slave /usr/sbin/ip6tables-restore ip6tables-restore /usr/sbin/ip6tables-nft-restore \
           --slave /usr/sbin/ip6tables-save ip6tables-save /usr/sbin/ip6tables-nft-save
         update-alternatives \
-          --install /usr/sbin/arptables arptables /usr/sbin/arptables-nft 20
+          --install /usr/sbin/arptables arptables /usr/sbin/arptables-nft 20 \
+          --slave /usr/sbin/arptables-restore arptables-restore /usr/sbin/arptables-nft-restore \
+          --slave /usr/sbin/arptables-save arptables-save /usr/sbin/arptables-nft-save
         update-alternatives \
-          --install /usr/sbin/ebtables ebtables /usr/sbin/ebtables-nft 20
+          --install /usr/sbin/ebtables ebtables /usr/sbin/ebtables-nft 20 \
+          --slave /usr/sbin/ebtables-restore ebtables-restore /usr/sbin/ebtables-nft-restore \
+          --slave /usr/sbin/ebtables-save ebtables-save /usr/sbin/ebtables-nft-save
 fi
 
 #DEBHELPER#