DOCSP-46310 EnumRepresentationConvention constructor update (#448)

Author: jordan-smith721

source/whats-new.txt

@@ -46,6 +46,18 @@ The 3.2 driver release includes the following new features:
   deserialized by the object serializer. To learn more about conventions,
   see the :ref:`csharp-conventions` guide.
 
+- Adds a new constructor for the ``EnumRepresentationConvention`` class that
+  allows you use the ``topLevelOnly`` parameter to specify whether the
+  convention applies to only enum properties or to all properties that include
+  collections of enums.
+
+  You can instantiate the ``EnumRepresentationConvention`` class by using the new
+  constructor as shown in the following example:
+
+  .. code-block:: csharp
+
+     EnumRepresentationConvention(BsonType representation, bool topLevelOnly);
+
 .. _csharp-version-3.1:
 
 What's New in 3.1