Link test 4: link with '{security-ref}' attribute

Author: kilfoyle

docs/en/ingest-management/troubleshooting/troubleshooting.asciidoc

@@ -4,6 +4,8 @@
 We have collected the most common known problems and listed them here. If your problem
 is not described here, please review the open issues in the following GitHub repositories:
 
+TEST3:  This investigation guide uses {security-guide}/osquery-placeholder-fields.html[placeholder fields] to dynamically pass alert data into Osquery queries.
+
 [options,header]
 |===
 | Repository | To review or report issues about