DOC: styler warnings in doc-build

[jreback]

https://travis-ci.org/pandas-dev/pandas/jobs/222779268

/tmp/doc/source/generated/pandas.io.formats.style.Styler.rst:74: WARNING: failed to import template:
/tmp/doc/source/generated/pandas.io.formats.style.Styler.rst:74: WARNING: toctree references unknown document 'generated/template:'

cc @TomAugspurger @jorisvandenbossche

I just pushed a change to fix the path of the imports (after pandas.formats change), but I think it still needs something.

[TomAugspurger]

Yeah saw that. I'll clean up the warnings in the doc build today.

[TomAugspurger]

For this specific one, it seems like it tries to auto-doc all of these

    Attributes
    ----------
    env : Jinja2 Environment
    template: Jinja2 Template
    loader : Jinja2 Loader

but template isn't a python module. I'll see if there's an easy way to skip just one.

[TomAugspurger]

For reference, there's the :exclude-members: template directive that might have worked. It's supposed to work with autodoc, but I haven't found anything about whether it works with autosummary. numpy/numpydoc#69 might be involved

I've turned those attributes into properties with their own docstings, and the warning is fixed.

I'll bush a batch of doc fixes a bit later today.

[jreback]

FYI @TomAugspurger this was just an incorrect usage of pytest.warn rather than tm.assert_produces_warning

[jreback]

sorry @TomAugspurger wrong issue.