Docs: Add front-matter to documentation-missing page

Author: phated

docs/documentation-missing.md

@@ -1,5 +1,11 @@
-## Excuse our dust!
+<!-- front-matter
+id: documentation-missing
+title: Documentation Missing
+hide_title: true
+-->
 
-We're in the process of rewriting **all** our documentation and some of the links we've added to completed docs haven't been written yet. You've likely clicked on one of those to end up here. We're sorry about that but please check back later on the topic you're interested in.
+# Excuse our dust!
+
+We're in the process of rewriting **all** our documentation and some of the links we've added to completed docs haven't been written yet. You've likely clicked on one of those to end up here. We're sorry about that but please check back later on the topic you're interested in. If you want to help out, we'll happily accept a Pull Request for this missing documentation.
 
 -The Gulp Team