`aria-haspopup` use requires the use of an ARIA `menu`, `listbox`, `tree`, `grid` or `dialog` (see https://www.w3.org/TR/wai-aria-1.1/#aria-haspopup)
in our use (as generic disclosure widgets), it's incorrect and sets up the wrong assumption/behavior from assistive technologies.
in future, we likely want to change our dropdowns to essentially be like a `dialog` - move focus to it when opened, possibly make it modal so focus is maintained inside it and the rest of the page
is hidden/inert.
but for now, removing the incorrect attribute is probably the quickest, most immediate fix.
- Move 4.1 docs to 4.2
- Update versions everywhere to 4.1.3 with release script
- Manually bump the shorthand version in package.json
- Add 4.2 to the versions docs page
- Update some redirects
- Fix tests asset URLs
- Bump Nuget and more
* SVG accessibility fixes
- add `focusable="false"` to all SVGs, to stop IE from including the `<svg>` in its default focus cycle
- completely hide decorative SVGs using `aria-hidden="true"`
- add `role="img"` to meaningful/"content" SVGs, ensure they have an appropriate `<title>` and/or `aria-label`
- simplify placeholder default title
* Simplify usage of placeholder.svg in the docs
- in most cases, no need for separate/redundant text and title (now that we make text itself part of the alternative text explicitly)
- no need (expect in rare cirumstances) to describe the placeholder image (unless the look of the image is important/the actual content, as is the case with the image thumbnail class)
* Simplify example.html rewriting of <svg> to <img> code sample
- as the `alt` for the placeholder isn't really important, just add an ellipsis instead (otherwise, to be correct, we'd have to construct the whole "title+text" construct like we do now in the
placeholder.svg itself
* Change svgo configuration to retain role attribute and add/force focusable=false
- regarding `focusable=false`, see https://github.com/svg/svgo/issues/1011 (which would be the "proper" SVGO fix) and the (hacky) solution https://github.com/svg/svgo/pull/817
Callouts are already excluded from ToC, but due to a limitation in jekyll-toc they are still being included.
We should revisit this if the bug is fixed later.
* Tweak the accessibility/reduced motion text
include mention of carousel slides, remove the (now inaccurate, as Firefox 63 includes it too) mention that support is limited to Safari/macOS
xref https://github.com/twbs/bootstrap/issues/27525
* Add new callout for reduced motion
* Add variable to control prefers-reduced-motion media query support
* Add callout about prefers-reduced-motion to all components currently using animation which are affected
