DOC: hiding cells with LaTeX

[eudoxos]

Please have a look at these small changes and consider adding them (in the form of this PR, or otherwise) to the documentation. Thanks!

[bsipocz]

Thanks @eudoxos for the PR. I cannot chime in reviewing for the latex part, but am going ahead and cherry-pick the first commit into a new PR (so we retrigger CI and will have a chance to fix RTD) and will go ahead with the merge.