Update current.html comment

_includes/nav/current.html

@@ -8,7 +8,7 @@
   {% assign _current = true %}
 <!--
   Use the page's `type` data key to connect the sidenav to a collection.
-  This sets "current" for the pages inside _posts and _security-updates directories.
+  This sets "current" for the pages inside the _posts directory.
   Collections are defined in config.yml, and "posts" is a default collection type in Jekyll.
 -->
 {% elsif page.collection and include.page.type == page.collection %}