R1:f29b54944f9c

Make closed objects in global typeahead look closed

Summary:
Fixes T6906.

I found the code in `behavior-search-typeahead.js` that was throwing away the closedness-detction work done in `Prejab.js::transformDatasourceResults`. Modified it to re-add the correct class name to the `phabricator-main-search-typeahead-result` elements.

Then I found some CSS in `typeahead-browse.css` and completely flailed around until realizing that particular CSS only gets loaded when hitting the typeahead endpoint directly.