DOCSP-45315: start_at_operation_time getter (#76)

Author: norareidy

source/read/change-streams.txt

@@ -124,7 +124,7 @@ Modify ``watch()`` Behavior
 
 You can modify the behavior of the ``watch()`` method by passing an instance
 of the ``mongocxx::options::change_stream`` class as a parameter. The following table
-describes the fields you can set in a ``mongocxx::options::find`` instance:
+describes the fields you can set in a ``mongocxx::options::change_stream`` instance:
 
 .. list-table::
    :widths: 30 70

source/whats-new.txt

@@ -37,6 +37,11 @@ What's New in 4.0
    {+driver-short+} v4.0 contains breaking changes. For more information, see
    :ref:`version-4.0-breaking-changes` in the Upgrade Driver Versions guide.
 
+The v4.0 driver release includes the following new features:
+
+- Adds a getter method for the ``start_at_operation_time`` field of a 
+  ``mongocxx::options::change_stream`` instance.
+
 .. _version-3.11:
 
 What's New in 3.11