* Restyle code element, clean up variables

- Removes the padding and background-color
- Changes the color to a brand color ()
- Add new variables to kbd element styles to account for removing the code ones
- Remove overrides that were needed previously

* only break between words, and override it in the pre

* make file inputs 100% wide

* scope custom file changes in input group for sizing

* shorter button labels for responsive

* narrower cards

* button was too wide

* downsize

* fewer links in pagination

* redo cell text

* improve overflow docs

IE10 and IE11 do not properly support the use of margin-auto on flex parents with a justify-content value other than flex-start. This PR removes the examples showcasing those two classes at play together in favor of simpler ones with _just_ the margin-auto utilities.

More details can be found at https://stackoverflow.com/a/37535548, which has been linked to from the docs as well.

Closes #24319 and closes #24413.

* rename order utilities to intended class names

* Documentation fixes.

follow up to #21436 to add docs for the .flex-row-reverse , .flex-column-reverse, and .flex-wrap-reverse

- Adds new flexbox.md file to utilities docs

- Adds a `breakpoints.yml` data file for easier output of responsive classes in the docs. Will put this to use on other pages soon.

- Adds hella flex utils. There are some dupes for now, but they'll get removed in time.