DOCSP-25436 Added a note about synchronous Java drivers. (#845)

* DOCSP-25436 Added a note about synchronous Java drivers.

* Updates made based on peer review of paired topic in docs-java

* Fixed a small typo

* Rewording based on peer review feedback.

Author: DBirtolo-mdb

source/reactive-streams.txt

@@ -29,6 +29,10 @@ or set up a runnable project by following our tutorials.
 
 - `Source Code <https://github.com/mongodb/mongo-java-driver/tree/master/driver-reactive-streams/>`__
 
+If you need to make synchronous calls between your application and MongoDB, use
+the :driver:`MongoDB Java Driver </java/sync/current/>` instead of the Reactive
+Streams Driver.
+
 Installation
 ------------