Now there's only one command needed to run the docs: `npm run docs-serve`.

Also, simplify the npm scripts.

* 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...

* 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