* Backport #32037

Add `.navbar-nav-scroll` for vertical scrolling of navbar content

* drop the css var for a Sass css

Co-authored-by: Mark Otto <markdotto@gmail.com>

Mention CSP and embedded SVGs in v4 docs

Add a live toast example to the docs

* Backport of changes to v5 docs that updated and clarified information about the Sass compiler used and the minimum rounding precision we recommend with it.

Co-authored-by: Mark Otto <otto@github.com>
Co-authored-by: XhmikosR <xhmikosr@gmail.com>

Co-authored-by: XhmikosR <xhmikosr@gmail.com>

* Clarify Sass import and customize docs for how to modify variable defaults

* Add an npm starter project callout to a few pages

They're links, acting as links. Just because they're styled as buttons visually (as is often the case for "Call to action" (CTA) links) doesn't mean they need/get `role="button"`

Co-authored-by: XhmikosR <xhmikosr@gmail.com>

* @babel/cli                   ^7.12.8  →  ^7.12.10
* @babel/core                  ^7.12.8  →  ^7.12.10
* @babel/preset-env            ^7.12.7  →  ^7.12.11
* @rollup/plugin-babel          ^5.2.1  →    ^5.2.2
* @rollup/plugin-commonjs      ^16.0.0  →   ^17.0.0
* @rollup/plugin-node-resolve  ^10.0.0  →   ^11.0.1
* autoprefixer                 ^10.0.2  →   ^10.2.1
* cross-env                     ^7.0.2  →    ^7.0.3
* eslint                       ^7.14.0  →   ^7.17.0
* eslint-config-xo             ^0.33.1  →   ^0.34.0
* eslint-plugin-unicorn        ^23.0.0  →   ^25.0.1
* find-unused-sass-variables    ^3.0.0  →    ^3.1.0
* hugo-bin                     ^0.66.2  →   ^0.68.0
* linkinator                    ^2.2.2  →   ^2.11.2
* nodemon                       ^2.0.6  →    ^2.0.7
* postcss                      ^8.1.10  →    ^8.2.3
* postcss-cli                   ^8.3.0  →    ^8.3.1
* qunit                        ^2.12.0  →   ^2.13.0
* rollup                 ...

Docs: Tweak the wording for collapse to indicate button is preferred/more semantic

Clarify the `$enable-shadows` option in our docs

Bump copyright year to 2021

While technically it still works, we're already saying authors shouldn't do it later on, and we removed any examples of this. This was a straggler.

Co-authored-by: XhmikosR <xhmikosr@gmail.com>

Fix popover docs example

Co-authored-by: XhmikosR <xhmikosr@gmail.com>

Co-authored-by: XhmikosR <xhmikosr@gmail.com>

* v4: Add an actual `data-touch="false"` example in the carousel docs

Backport of https://github.com/twbs/bootstrap/pull/32638



* Remove data-ride from example carousel

* Correct attribute table explanation and remove slide class from example

i believe the correct option is `slide` here, not `ride`.
the `if "carousel"` bit was rather unclear/confusing

* Edits...

sorry, trying to make sense of our quirky carousel stuff, it seems some illogical things have been there ever since

* Add data-interval to suppress autoplay

* Tweak carousel options formatting

* Update site/content/docs/4.5/components/carousel.md

Co-authored-by: Mark Otto <markd.otto@gmail.com>

* Tweak language

mostly based on @mdo

's suggestion, but also adds the word "attribute" after `data-ride` for better flow/legibility

Co-authored-by: Mark Otto <markd.otto@gmail.com>

v4 backport: Replace Lorem Ipsum placeholder text with more representative (or at least english language) text (#32462)

Backport and expansion (for v4) of #32246 and #32479

* Revert colors.yml accidental changes

* Bring colors data files up to par with the vars

* Update _syntax.scss with the latest chroma selectors

* Sort selectors

* Remove no longer needed chroma workaround

* remove comments

docs: use `event` instead of `e`

Be consistent with Popper's name.

docs(dropdowns): clarify where is `.show` applied

Co-authored-by: XhmikosR <xhmikosr@gmail.com>

Moving it to the CodePen org so that we can all edit it.

Switch to jsDelivr for the remaining docs assets

Also, update feather icons and chart.js

Now, it's safe to do use it since it covers more cases

This commit includes all the needed workarounds and most changes from the main branch for everything to work, like:

* removing empty lines in raw HTML that break output
* read .browserslistrc, CSS variables from disk instead of duplicating it
* using Hugo mounts
* using Hugo for the docs CSS/JS
* move ToC Sass code to a separate file while adapting it for Hugo

Thus, this patch makes our npm scripts faster since lint runs on one step and there's no separate docs assets processing.