docs nat: fix nat-ha ascii art
See:
Type: docs
@@ -13,6 +13,7 @@ Session synchronization traffic is distributed through an IPv4 UDP connection. T
The two NAT nodes have a dedicated link (interface GE0/0/3 on both) to synchronize NAT sessions using NAT HA protocol.
+```
+-----------------------+
| outside network |
+-----------------------+
@@ -36,6 +37,7 @@ The two NAT nodes have a dedicated link (interface GE0/0/3 on both) to synchroni
+-----------------------+
| inside network |
+-----------------------+
+```
### Active node configuration
