Add missing return None in except clause to pseudo-code. (#1205)

Author: YannickJadoul

pep-0553.rst

@@ -195,6 +195,7 @@ feature looks roughly like the following::
                 'Ignoring unimportable $PYTHONBREAKPOINT: {}'.format(
                     hookname),
                 RuntimeWarning)
+            return None
         return hook(*args, **kws)
 
     __breakpointhook__ = breakpointhook
@@ -239,6 +240,10 @@ which inherits several of the problems this PEP aims to solve.
 Version History
 ===============
 
+* 2019-10-13
+
+  * Add missing ``return None`` in ``except`` clause to pseudo-code.
+
 * 2017-09-13
 
   * The ``PYTHONBREAKPOINT`` environment variable is made a first class