Add changes to changelog

Author: paulbalandan

user_guide_src/source/changelogs/v4.2.0.rst

@@ -29,6 +29,8 @@ Enhancements
 - Added new OCI8 driver for database.
     - It can access Oracle Database and supports SQL and PL/SQL statements.
 - The ``spark routes`` command now shows closure routes, auto routtes, and filters. See :ref:`URI Routing <spark-routes>`.
+- Exception information logged through ``log_message()`` has now improved. It now includes the file and line where the exception originated. It also does not truncate the message anymore.
+    - The log format has also changed. If users are depending on the log format in their apps, the new log format is "<1-based count> <cleaned filepath>(<line>): <class><function><args>"
 
 Changes
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