[cleanup] Fix some flake8 errors and drop upper bound of copyright along the way. autoform module is not added to flake8-ok-files since there are some remaining errors to be handled, but that's still a start.

.. _req_module:

:mod:`cubicweb.req`
===================

.. automodule:: cubicweb.req

    .. autoexception:: FindEntityError

    .. autoclass:: RequestSessionBase
        :members: