Use our example shortcode's `class` parameter instead.

Improvement to better understand how utilities class name are generated by the (_api.scss) base in the line of code below:
`$property-class: if($property-class, $property-class, nth($properties, 1));`

https://github.com/twbs/bootstrap/blob/fc02932946424e986a72bb7b47044eab815851cb/scss/mixins/_utilities.scss#L21

* 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...

* Prevent .sr-only-focusable overriding properties when being focused

* Typo

* Move close icon to components

* Remove redundant float from close

- Deletes mixin mentions from float docs
- Deletes mixin mention from visibility docs
- Deletes the image-replacement page for text-hide

This allows for the build to fail if a reference isn't found.

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