#3 fixes section header showing underneath breadcrumbs header

[zsinnema]

No description provided.

[kmantel]

This issue shows up in several other places with different levels of nested section tags. Some examples which would be missed by article > section > section:
https://princetonuniversity.github.io/PsyNeuLink/Composition.html#composition
https://princetonuniversity.github.io/PsyNeuLink/Composition.html#graph
I think just section would be ok for this.

There are also some screen-size-aware rules for psyneulink-page-level-bar that cause this problem not to occur on some screen sizes, so it would be good to handle these cases also, to avoid extra whitespace.
See
https://github.com/kmantel/psyneulink-sphinx-theme/blob/622332fe9cf3173f1ba910ead8707c372e552fc9/psyneulink_sphinx_theme/static/css/theme.css#L10874-L10916=

[zsinnema]

@kmantel yes I think it can be set on just section. See my last commit. I also wrapped it in a @media query to only apply when screen sizes > 1100px.

[kmantel]

lgtm, thanks!