DOCSP-37238 Add note about transactions to bulk update (#606)

* DOCSP-37238 Add note about transactions to bulk update

* *

* *

Author: ianf-mongodb

source/documents/modify-multiple.txt

@@ -28,6 +28,10 @@ About this Task
 - The :guilabel:`Update Documents` modal does not support any ``options`` 
   parameters such as upsert, writeConcern, or collation.
 
+- Previews of the documents affected by bulk update operations are 
+  only visible if your database is configured to support transactions.
+  For details, see :ref:`transactions`. 
+
 Before you Begin
 ----------------