Document the trace server setting is valid (despite Code's warning) (#3544)

Add this additional note as VS Code does not recognize this setting. The result is: 'Unknown Configuration Setting'.
#3543 (comment)

Author: Michał Kozakiewicz

docs/troubleshooting.md

@@ -263,6 +263,8 @@ In some cases, getting to the bottom of a bug will require looking at the payloa
   ```json
   "powershell editor services.trace.server":"verbose"
   ```
+  
+> NOTE: While VSCode will not recognize and highlight it, it is a valid option and enables tracer logs on the server.
 
 - Restart Visual Studio Code and reproduce the issue.