* Initial spike of consolidated form checks

* Stub out forms rearrangement

- Prepping to drop non-custom file and range inputs
- Prepping to merge custom and native checks and radios (with switches)
- Prepping to merge custom select with form select
- Moving docs arround so forms has it's own area given volume of CSS

* Move input group Sass file to forms subdir

* Start to split and move the docs around

* Simpler imports

* Copyediting

* delete overview file

* Remove commented out code

* remove the custom-forms import

* rewrite flex-check as form-check, replace all custom properties

* Remove old forms doc

* stub out new subpage link section

* update migration guide

* Update nav, forms overview in page nav, and descriptions

* fix check bg position

* fix margin-top calculation

* rename .custom-select to .form-select

* Update validation styles for new checks

* add some vertical margin, fix inline checks

* fix docs examples

* better way to do this contents stuff, redo the toc while i'm at it

* page restyle for docs while here

* un-callout that, edit text

* redo padding on toc

* fix toc

* start to cleanup checks docs

* Rewrite Markdown tables into HTML

* Redesign tables, redo their docs

* Replace Open Iconic icons with custom Bootstrap icons

* Redesign the docs navbar, add a subheader, redo the sidebar

* Redesign docs homepage a bit

* Simplify table style overrides for docs tables

* Simplify docs typography for page titles and reading line length

* Stub out icons page

* Part of sidebar update, remove migration from nav.yml

* Move toc CSS to separate partial

* Change appearance of overview page

* fix sidebar arrow direction

* Add footer to docs layout

* Update descriptions

* Drop the .form-group class for margin utilities

* Remove lingering form-group-margin-bottom var

* improve footer spacing

* add headings to range page

* uncomment form range css

* Rename .custom-range to .form-range

* Drop unused docs var

* Uncomment the comment

* Remove unused variable

* Fix radio image sizing

* Reboot update: reset horizontal ul and ol padding

* de-dupe IDs

* tweak toc styles

* nvm, fix dropdown versions stuff

* remove sidebar nav toggle for now

* broken html

* fix more broken html, move css

* scss linting

* comment out broken helper docs

* scope styles

* scope styles

* Fixes #25540 and fixes #26407 for v5 only

* Update sidebar once more

* Match new sidenav order

* fix syntax error

* Rename custom-file to form-file, update paths, update migration docs for previous changes in #28696

* rename back

* fix size and alignment

* rename that back too

* Remove unused classes/styles and use utilities instead of specific styles
* Use `getElementById` instead of `querySelector`

No more Ruby dependency and most important more than 10 times less build time (at least on Windows)!

There's no reason for us to wait here.

Some of the snippets need to be updated later.

* Prep for v4.3.0

* More updates for v4.3.0.

* rerun to build docs source map

- Move 4.1 docs to 4.2
- Update versions everywhere to 4.1.3 with release script
- Manually bump the shorthand version in package.json
- Add 4.2 to the versions docs page
- Update some redirects
- Fix tests asset URLs
- Bump Nuget and more

This reverts commit b04f97f6.

This allows us to generate the anchor links on build time.

https://github.com/allejo/jekyll-anchor-headings

(again)

https://github.com/twbs/bootlint/wiki/W007

With the current docs directory setup, I'm making too many mistakes and have to manually address path changes and directory moves on deploy. This makes for a frustrating experience developing locally and shipping releases. With this PR, we're basically back to the same setup from v3—duplicating the dist directory into our docs directory. Not the most ideal, but very straightforward for me as the release manager.

Also, move the search code to a separate file.

Rely on `site.url` which is different for production. In that case do nothing with the search result, otherwise when in development remove our url from it.

Previously a search redirected to `https://getbootstrap.com/...`

* Update copyright range to include 2018

* Extend copyright date range on new files from 2017 to include 2018

This makes them keyboard-accessible. For mouse users, the only change
here is that the focus outline will remain on the button once clicked
(in future, this can be solved with :focus-ring, but for now this would
require a polyfill). the tooltip is explicitly hidden on `mouseleave`,
so even though the `<button>` retains focus after clicking, the tooltip
won't stay visible once mouse user moves away.
the mouse hover styles have explicitly not been make to also apply to
:focus, so as to minimise the visual impact for
mouse users (though the tooltip remains visible)
 - but due to the default outline and the custom tooltip, it
should be fairly clear when keyboard users set focus to a copy button
too.