here added 4th level menu items where appropriate in io.rst.
might pay to do this somewhat in some other sections just to break the sub-sections up a bit - http://pandas-docs.github.io/pandas-docs-travis/dsintro.html
maybe other places as well
Comment From: jorisvandenbossche
Now, in general, I would rather keep it to 3 levels, and split it in multiple files instead of keeping expanding the current files. See #10446
(but just for now making it better navigatable, having 4 levels is OK, for the long term I would go with #10446)
Comment From: jreback
yes, it IS prob better to simply split io.rst up. Though it will still need to be 4 levels even if we do that :<
Comment From: jreback
though was thinking in the Intro section, their are a lot of bullet points,, this is just some organization to it .... my 2c
Comment From: jorisvandenbossche
Let's close this, we have issues about splitting that page, and the new docs theme will try to handle this case better as well.