following on from https://github.com/twbs/bootstrap/pull/35213 this

- expands the note, making it clear it's not supported
- makes it a callout

- a few rewordings/tweaks
- add info about toasts with focusable/actionable controls (shouldn't autohide them)

manual backport of https://github.com/twbs/bootstrap/pull/33810

* Use param to set Bootstrap version in Contents doc

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

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

Manual backport of https://github.com/twbs/bootstrap/pull/33797

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

manual backport of #34886

per https://www.w3.org/TR/html-aria/#docconformance

> It is NOT RECOMMENDED to use `aria-disabled="true"` on an `a` element with an `href` attribute.
>
>NOTE
>If a link needs to be "disabled", remove the `href` attribute.

This PR removes the unnecessary `href="#"`, `tabindex="-1"`, and `aria-disabled="true"` from disabled links in both docs pages and examples. `aria-disabled="true"` *is* kept for disabled link-based buttons (that have `role="button"`) as there it's appropriate to use (you *want* to convey to assistive technologies that this thing you're claiming is a button is also disabled at the moment)

Further, the PR extends the "Link functionality caveat" to show the "proper" way (removing `href` and adding `.disabled` class only) to disable a link, but then explains what to do if that's not possible (and then keeps an example with all the traditional `href="#" tabindex="-1" aria-disabled="true"`, but explains clearly that it's not ideal). Same sort of explanation is also added to the pointer event utilities page

Remove unneeded `.text-white-50` CSS rule

This is already part of Bootstrap 4.6 and 5.0.

`aria-haspopup="true"` is really intended to signal that an ARIA `menu` will be opened on activation. as a result, some assistive technologies will announce controls with `aria-haspopup="true"` as a menu or menu item (e.g. JAWS and NVDA).
In addition, `aria-haspopup` seems to trigger a bug in Edge/Narrator where the `aria-expanded` state is not correctly announced at the moment when `aria-haspopup` is present.
This now makes the dropdown button more like a generic disclosure widget control - see also https://www.w3.org/TR/wai-aria-practices-1.2/examples/disclosure/disclosure-navigation.html01

Carousel: use buttons, not links, for prev/next controls

* Update the default value for $enable-deprecation-messages

As seen in the https://github.com/twbs/bootstrap/blob/v4-dev/scss/_variables.scss,
the `$enable-deprecation-messages` variable is set to `true` by default.

* Add a callout for the sanitizer in popovers and tooltips

* Add second reference to sanitizer in the options

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

* Bump version to v4.6.0.

* Dist

* 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>

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

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

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>

* 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>