Add entry for datasweet formula plugin (#16868) (#19166)

docs/plugins/known-plugins.asciidoc

@@ -60,6 +60,6 @@ This list of plugins is not guaranteed to work on your version of Kibana. Instea
 Use it to create, edit and embed visualizations, and also to search inside an embedded dashboard.
 
 * https://github.com/sw-jung/kibana_markdown_doc_view[Markdown Doc View] (sw-jung) - A plugin for custom doc view using markdown+handlebars template.
-
+* https://github.com/datasweet-fr/kibana-datasweet-formula[Datasweet Formula] (datasweet) - enables calculated metric on any standard Kibana visualization.
 
 NOTE: If you want your plugin to be added to this page, open a {repo}tree/{branch}/docs/plugins/known-plugins.asciidoc[pull request].