v5 documentation new look and feel (meta bug)

seems https://github.com/twbs/bootstrap/pull/28450 introduced a large number of changes not only to forms, but to the actual look and feel of the v5 version of getbootstrap.com

a few initial problems/issues noted with that (please feel free to add more):

• contrast in the top navigation bar for the links/icons falls below 4.5:1
• left-hand navigation scrolling is borked when the nav and page get long (you have to scroll all the way to the end of the content before the left-hand navigation scrolls
• once the navigation has expand/collapse disclosure widgets, they lack a role="button" and aria-expanded="true"/aria-expanded="false"
• hover-specific styles for the top nav, breadcrumbs, left-hand navigation, which are not applied on :focus ... so they're all niceties and styles that only work for mouse users, not keyboard users; need doubling up of :hover and :focus styles
• some changes were introduced to _tables.scss which don't make sense: https://github.com/twbs/bootstrap/pull/28450/files#diff-82ee1ffb694a87db828fe22dcd868aed
• left-hand navigation also blows up in IE11 - will be fixed in #29029
• Move any inline script code to application.js
• The docs no longer have their toggler so there's no way to navigate the docs on mobile
• Use our collapse plugin in the sidebar
• Add transition in the sidebar arrow transform
• Maybe we should move forms under components since they are components themselves
• IE11 shrinks the search field