DOCSP-20589-release-notes-for-param-update (#183)

* DOCSP-20589-release-notes-for-param-update

* Review feedback

Author: Dave

source/changelog.txt

@@ -181,6 +181,10 @@ New features in this release:
   ``// comments`` are now preserved as ``/* comments */`` in the
   history entry.
 
+- The :ref:`aggregation-pipeline` parameter is now optional for
+  :method:`db.collection.watch()`, :method:`db.watch()`, and
+  :method:`Mongo.watch()`.
+
 Bug Fixes in this Release:
 
 - ``mongosh`` now runs aggregations with :pipeline:`$out` or