DOCSP-43551: json encoding v5.2 (#174)

Author: rustagir

source/whats-new.txt

@@ -34,6 +34,12 @@ New features of the 4.11 driver release include:
 
       :ref:`kotlin-search-indexes` in the Indexes guide
 
+- Supports serialization of `JsonElement
+  <{+kotlin-docs+}/api/kotlinx.serialization/kotlinx-serialization-json/kotlinx.serialization.json/-json-element/>`__
+  values. To work with the ``JsonElement`` type, you must add the
+  ``kotlinx-serialization-json`` library as a dependency in your
+  application.
+
 .. _kotlin-coroutine-version-5.1.3:
 
 What's New in 5.1.3