fix: snif readme updates

Author: DhanushNehru

Black Hat Python/chapter_03/README.md

@@ -1,6 +1,12 @@
 ### sniffer_basic.py
 
-```
+```bash
 sudo python3 sniffer_basic.py 
 ```
-If running in local machine input the ip address which can be got by running `ipconfig` on Windows and `ipconfig getifaddr en0` on macOS
+If running in local machine input the ip address which can be got by running `ipconfig` on Windows and `ipconfig getifaddr en0` on macOS
+
+Open another terminal pick a host to ping.
+```bash
+ping google.com 
+```
+Then you should see some garbled output