Misc/NEWS.d/next/Core and Builtins/0404.bpo-23722.e8BH5h.rst

Rather than silently producing a class that doesn't support zero-argument
``super()`` in methods, failing to pass the new ``__classcell__`` namespace
entry up to ``type.__new__`` now results in a ``DeprecationWarning`` and a
class that supports zero-argument ``super()``.