Add symantec to the list of firewalls which blocks WSL

As stated on:

- microsoft/WSL#4926 (comment)
- microsoft/WSL#5382 (comment)

Author: felipecrs

WSL/faq.md

@@ -195,6 +195,7 @@ Some users have reported issues with specific firewall applications blocking int
 1. Kaspersky
 1. AVG
 1. Avast
+1. Symantec Endpoint Protection
 
 In some cases turning off the firewall allows for access. In some cases simply having the firewall installed looks to block access.
 

WSL/troubleshooting.md

@@ -233,6 +233,7 @@ Some users have reported issues with specific firewall applications blocking int
 1. Kaspersky
 2. AVG
 3. Avast
+4. Symantec Endpoint Protection
 
 In some cases turning off the firewall allows for access.  In some cases simply having the firewall installed looks to block access.