The `-all` directives should not take any content. Taking content
is now an error.

This means that someone who writes:

.. ...-skipa-all::

   >>> content

will now fail in sphinx.  Previously the content was expected and then
doctestplus choked on expecting content

Co-authored-by: Stuart Mumford <stuart@cadair.com>

seberg deleted the fix-directives branch

pllim mentioned this pull request