docs: update http api index

docs/sources/http_api/index.md

@@ -21,6 +21,9 @@ dashboards, creating users and updating data sources.
 * [Authentication API]({{< relref "/http_api/auth.md" >}})
 * [Dashboard API]({{< relref "/http_api/dashboard.md" >}})
 * [Dashboard Versions API]({{< relref "http_api/dashboard_versions.md" >}})
+* [Dashboard Permissions API]({{< relref "http_api/dashboard_permissions.md" >}})
+* [Folder API]({{< relref "/http_api/folder.md" >}})
+* [Folder Permissions API]({{< relref "http_api/folder_permissions.md" >}})
 * [Folder/dashboard search API]({{< relref "/http_api/folder_dashboard_search.md" >}})
 * [Data Source API]({{< relref "http_api/data_source.md" >}})
 * [Organisation API]({{< relref "http_api/org.md" >}})