Validator's autodoc is missing some attributes

[funkyfuture]

The instance attributes set in Validator.__init__ are missing in the API docs, eg. document.

At least Sphinx 1.5.6 or newer also spits out warnings. i tried the autoattribute and autoinstanceattribute without success so far.

[stroykova]

sphinx project has two open issues about it: 6415 741 and no workaround