resync docs with YARD docstrings
add better warning to prevent direct editing of auto-gen docs
correct div.class wrapping of searchable filters
Merge pull request #2611 from vanburg/2610-correct-wrapping-searchable-filters

Don't apply the select_and_search styles if the filter method itself is searchable
update menu docs as per conversation in #2397
copy update for 2-resource-customization.md
convert 2-resource-customization.md to GFM :octocat:
simplify examples in 2-resource-customization.md
update index docs to use GFM :cake: