Add missing description

Author: peholmst

Diff for: articles/contributing/docs/types.adoc

@@ -1,6 +1,7 @@
 ---
 title: Types of Documentation
 page-title: Types of Documentation | How to contribute to Vaadin Documentation
+description: Learn about the different types of Vaadin documentation - how-to guides, reference manuals, and deep dives - and understand best practices for writing each type effectively.
 meta-description: Learn about the different types of Vaadin documentation - how-to guides, reference manuals, and deep dives - and understand best practices for writing each type effectively.
 order: 5
 ---