Prevent overflowing static backdrop modal animation

TODO: backport the test too

Prevent overflowing static backdrop modal animation

TODO: backport the test too

* Remove backdrop-filter from toasts

* BrowserStack: test on Edge 15

* Backport twbs#31135

* Move color utility callouts to start of page

Hierarchically/structurally, in the position they are currently at, the two callouts seem like they "belong" just to the "background color" section. Moving them to the start makes it clearer that those two callouts relate to everything in the page (both "Color" and "Background color" classes.

* Change heading level

otherwise the assistive technology callout looks like it's hierarchically under the "Dealing with specificity" heading

* Backport twbs#30326

Prevent overflowing static backdrop modal animation

TODO: backport the test too

* Backport twbs#30326 (Unit test)

* Update Babel config (twbs#31011)

* remove plugin-proposal-object-rest-spread
* add bugfixes
* `exclude: ['transform-typeof-symbol']` did nothing with our config

* Update devDependencies and gems

* Update dependencies, gems and regenerate package-lock.json (twbs#31261)

* @rollup/plugin-node-resolve 8.1.0
* popper.js 1.16.1
* qunit 2.10.1
* rollup 2.21.0

* Docs: forms accessibility cleanup (backport from v5) (twbs#31234)

* Expand advice for anchor-based controls

* Expand accessibility note in input group

* Correct statement about validation, fix server example

* Tweak label > accessible name

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

* Turn off scroll anchoring for accordions (twbs#31347)

New default behavior for scroll anchoring (rolled out in Chrome 84?) leads to unsightly/odd accordion interactions - see twbs#31341
This rule suppresses this new behavior and reverts back to the old way.

See https://drafts.csswg.org/css-scroll-anchoring/

* Update to Ruby 2.7/Bundler 2.x. (twbs#31296)

* Clear timeout before showing the toast (twbs#31155)

* clear timeout before showing the toast

* Add unit test

* Remove the check for timeout

* Check for clearTimeout to have been called

Co-authored-by: XhmikosR <xhmikosr@gmail.com>
# Conflicts:
#	js/tests/unit/toast.spec.js

* Add unit test for toast to check clearTimeout to have been called (twbs#31298)

* docs(skippy): prevent skip links from overlapping header

* Backport twbs#31344

Add toasts to the components requiring JavaScript

* Update devDependencies and gems

* @babel/cli                   ^7.10.4  →  ^7.11.0
* @babel/core                  ^7.10.4  →  ^7.11.0
* @rollup/plugin-babel          ^5.0.4  →   ^5.1.0
* @rollup/plugin-commonjs      ^13.0.0  →  ^14.0.0
* @rollup/plugin-node-resolve   ^8.1.0  →   ^8.4.0
* autoprefixer                  ^9.8.4  →   ^9.8.6
* eslint                        ^7.4.0  →   ^7.6.0
* karma                         ^5.1.0  →   ^5.1.1
* rollup                       ^2.21.0  →  ^2.23.0

* Remove overflow: hidden from toasts (twbs#31381) (twbs#31407)

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

* Backport twbs#31339 (twbs#31414)

* Backport twbs#31339

Add view on GitHub links for easier content editing from the docs

* Prepare v4.5.1. (twbs#31408)

* Remove flex: 1 0 100% from rows (twbs#31439) (twbs#31445)

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

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

* Restore make-container-max-widths mixin

* Deprecate the `make-container-max-widths` mixin

* Remove undefined `$ignore-warning`

* Prepare v4.5.2. (twbs#31444)

Co-authored-by: Mark Otto <markd.otto@gmail.com>
Co-authored-by: XhmikosR <xhmikosr@gmail.com>
Co-authored-by: ysds <ysds.code@gmail.com>
Co-authored-by: Patrick H. Lauke <redux@splintered.co.uk>
Co-authored-by: Rohit Sharma <rohit2sharma95@gmail.com>
Co-authored-by: Gaël Poupard <gael.poupard@orange.com>
Co-authored-by: Martijn Cuppens <martijn.cuppens@gmail.com>

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