IPv6 docs: The ARP cache is called NDP neighbor cache in IPv6

Signed-off-by: Malte Janduda <mail@janduda.net>

docs/sources/articles/networking.md

@@ -578,9 +578,10 @@ for Docker. When adding a third host you would add a route for the subnet
 
 Remember the subnet for Docker containers should at least have a size of `/80`.
 This way an IPv6 address can end with the container's MAC address and you
-prevent ARP cache invalidation issues in the Docker layer. So if you have a
-`/64` for your whole environment use `/68` subnets for the hosts and `/80` for
-the containers. This way you can use 4096 hosts with 16 `/80` subnets each.
+prevent NDP neighbor cache invalidation issues in the Docker layer. So if you
+have a `/64` for your whole environment use `/68` subnets for the hosts and
+`/80` for the containers. This way you can use 4096 hosts with 16 `/80` subnets
+each.
 
 Every configuration in the diagram that is visualized below the dashed line is
 handled by Docker: The `docker0` bridge IP address configuration, the route to