Docs: Mention setting for running tests in VS Code

Author: shati-patel

docs/codeql/codeql-for-visual-studio-code/customizing-settings.rst

@@ -62,6 +62,8 @@ Configuring settings for testing queries
 
 To increase the number of threads used for testing queries, you can update the **Running Tests > Number Of Threads** setting.
 
+To pass additional arguments to the CodeQL CLI when running tests, you can update the **Running Tests > Additional Test Arguments** setting. For more information about the available arguments, see "`test run <https://codeql.github.com/docs/codeql-cli/manual/test-run/>`_" in the CodeQL CLI help. 
+
 Configuring settings for telemetry and data collection
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