Leaking tooltips across tests leads to confusion and sadness.

Fixes #13696.
Fixes #13696.
Fixes #14197.
Closes #13718.

Fixes #13031.

Fixes #14483

Fixes #12815.
Closes #14363.

Added handling of aria-expanded=true/false to collapse.js, updated
documentation to include advice on making expand/collapse controls
accessible, updated examples and javascript documentation to use
aria-expanded and aria-controls (when targetting single collapsible
element, using ID rather than class selector)

Closes #14147.
Closes #14153.

Fixes #13071

If opening a modal when a scrollbar is present, closing it, then
resizing the window so the scrollbar disappears, then opening the
modal again, the content would shift. This fixes the problem by
always calculating the scrollbar width every time a modal is opened.

Closes #14357.

Closes #14093
Correction to #14090
Relevant docs: https://developer.mozilla.org/en-US/docs/Web/API/Element.getBoundingClientRect#Browser_compatibility

- is(':visible') seems to be the only reliable check, without a refactoring of how hoverState is used
- tests need improvement

[skip validator]

Fixes #14241

[skip validator]

Also adds another test for #9461: carousel next/prev should ignore non-items

  document height is smaller than the viewport height.

  in order to handle multiple edge cases, specifically when the document
  height is dynamic.
Always reposition an affix that is affixed to the bottom.

Refs #14090.
Also, fix one typo.