Update docs

Author: cscarpitta

nets-in-progress/8r-1c-srv6-pm/README.md

@@ -10,6 +10,7 @@ This topology is the same as 8r-1c-out-band, but same nodes are configured to ru
 
 ## Start the topology
 
+To start the topology:
 ```
 python isis8d.py
 ```

nets-unmantained/8r-1c-out-band-isis/README.md

@@ -8,6 +8,7 @@ A Mininet topology with 8 routers running IS-IS routing protocol, 12 hosts, 3 da
 
 ## Start the topology
 
+To start the topology:
 ```
 python isis8d.py
 ```

nets/8r-1c-in-band-isis/README.md

@@ -10,6 +10,7 @@ This topology has been used in [ROSE-SRv6 tutorial on Linux - Part 2](https://do
 
 ## Start the topology
 
+To start the topology:
 ```
 python isis8d.py
 ```