Update Perf Capture settings in "Analyze runtime performance" (#3638)

* update Settings checkboxes

* slow then optz

* steps lead-in

* demo's option buttons

* concat sys response

* concat h2 intro

* flatten

* icons, inc cmts

* fill page w/ ideal # icons

* heading Fill page w number of icons

* Step headings

* headings polish

* dark-icons border

* linkfix

* sep. action vs result

Author: mikehoffms