Add work-in-progress to intro

Author: lcawl

docs/overlays/elasticsearch-openapi-overlays.yaml

@@ -9,10 +9,14 @@ actions:
     update:
       title: Elasticsearch API
       description: >
+        Elasticsearch provides REST APIs that are used by the UI components and can be called directly to configure and access Elasticsearch features.
+        
         ## Documentation source and versions
         
         This documentation is derived from the `main` branch of the [elasticsearch-specification](https://github.com/elastic/elasticsearch-specification) repository.
         It is provided under license [Attribution-NonCommercial-NoDerivatives 4.0 International](https://creativecommons.org/licenses/by-nc-nd/4.0/).
+
+        This documentation contains work-in-progress information for future Elastic Stack releases.
       x-doc-license:
         name: Attribution-NonCommercial-NoDerivatives 4.0 International
         url: 'https://creativecommons.org/licenses/by-nc-nd/4.0/'