Move the search icon back to the sidebar to make it easier to find and use #746
Description
In 1.0, we adopted the PyData Sphinx Theme "in-page search icon" for our search:
However a number of folks have noted that this is a difficult place to notice, and it degrades the UX of finding and using search. Instead, we should default our search bar to be in the sidebar where it often is for these kinds of single sidebar themes.
This PR in the PyData theme makes this pretty easy to do here: