Running `./build/change-version.js v4.0.0-alpha.6 v4.0.0` fixed this,
so the version change script works fine. I'm presuming instead this
change was just omitted from 35f80bb1, and then wouldn't have
been caught by subsequent runs of `change-version`, since it only
ever replaces the exact old version string specified.

This variable is not used anywhere.

Leftover from #18373.

* Dropdown - Allow to disable Popper.js style

* Update dropdown.js

* Update dropdown.html

* copy changes

Less on 2 symbols

This commit allows nested structures for accordions. Also a part of
the documentation about data-children is removed because this
functionality didn't work and it's not applicable anymore.

Tests with the collapse accordion are also a bit adjusted to the new
situation.

* Add dropright (right placement for our dropdown)

* Add dropleft

* moves drop left arrow to the left

We don't support Opera 12, and Firefox's property was the unprefixed one.

Fix for issue #24117

* Offset option can be function (Popper.js)

* Fix...add function type for offset option

* Remove constants for popper config

* Optimize code. Remove foreach loop.

* Refactoring. Remove getOffset method

* Use `aria-selected` instead of `aria-expanded`
* Change tab.js to use `aria-selected` rather than `aria-expanded`
* Add `aria-orientation=vertical` to vertical tab list
* Remove dynamic tabs with dropdowns
* Fix non-interactive code examples
* Only set `aria-selected` on the `role="tab"` trigger - this stops `aria-selected` being incorrectly added to the `role="tabpanel"` itself (probably harmless, but nonetheless incorrect)