[11.x] Documents removeAllFromSearch method (#9676)

* documents removeAllFromSearch method

* Update scout.md

---------

Co-authored-by: Taylor Otwell <taylor@laravel.com>

Author: christopherarter

scout.md

@@ -595,6 +595,10 @@ Or, if you already have a collection of Eloquent models in memory, you may call
 
     $orders->unsearchable();
 
+To remove all of the model records from their corresponding index, you may invoke the `removeAllFromSearch` method:
+
+    Order::removeAllFromSearch();
+
 <a name="pausing-indexing"></a>
 ### Pausing Indexing