bpo-33559: Attribute changed repr of exceptions (GH-6954)

Author: hroncok

Doc/whatsnew/3.7.rst

@@ -1240,6 +1240,7 @@ Changes in the Python API
 
 * ``repr`` for :exc:`BaseException` has changed not to include trailing comma
   in the output. Mind that most exceptions are affected by this change.
+  (Contributed by Serhiy Storchaka in :issue:`30399`.)
 
 * ``repr`` for :class:`datetime.timedelta` has changed to include keyword arguments
   in the output. (Contributed by Utkarsh Upadhyay in :issue:`30302`.)