add What's New entry

Author: picnixz

Doc/whatsnew/3.15.rst

@@ -78,6 +78,11 @@ Other language changes
 * Several error messages incorrectly using the term "argument" have been corrected.
   (Contributed by Stan Ulbrych in :gh:`133382`.)
 
+* :func:`sys.exit` and :exc:`SystemExit` now correctly handle empty and 1-item
+  tuples arguments. Previously, such tuples were unpacked by :func:`!sys.exit`
+  but not by :exc:`!SystemExit` and the process status code was incorrectly
+  set.
+  (Contributed by Bénédikt Tran in :gh:`133548`.)
 
 
 New modules