adding code bock

docs/network_chaos.md

@@ -18,7 +18,7 @@ network_chaos:                                    # Scenario to create an outage
 ```
 
 ##### Sample scenario config for ingress traffic shaping (using a plugin)
-'''
+```
 - id: network_chaos
   config:
     node_interface_name:                            # Dictionary with key as node name(s) and value as a list of its interfaces to test
@@ -35,7 +35,7 @@ network_chaos:                                    # Scenario to create an outage
         bandwidth: 10mbit
     wait_duration: 120
     test_duration: 60
-  '''
+```
 
   Note: For ingress traffic shaping, ensure that your node doesn't have any [IFB](https://wiki.linuxfoundation.org/networking/ifb) interfaces already present. The scenario relies on creating IFBs to do the shaping, and they are deleted at the end of the scenario.