added detail on new metadata tag to formatting section too

Author: DougAnsonAustinTX

content/learning-paths/cross-platform/_example-learning-path/appendix-1-formatting.md

@@ -300,4 +300,13 @@ You can also give a custom title as specified here.
 - Work
 {{% /notice %}}
 
+## Hiding a page from being listed in the navigation pane
+
+Use the following metadata in your markdown page to effectively "hide" the page from being listed in the navigation pane:
+
+```markdown
+---
+hide_from_navpane: true
+---
+```