* Replace element.offet* by getBoundingClientRect()

* Use variable to store BoundingClientRect

* Fix cc issue...

* Fix getSelectorFromElement when # is a selector

* Thanks to @vanduynslagerp remove regex to validate selector

- Create backdrop only if the menu is actually open (do not create it if the show event is prevented)
- Drop the backdrop only when the corresponding menu is closed (do not remove if there is no menu to close or if the hide event is prevented)

* Allow to use Tab.js with list-group

* Allow to use list-group with div parent instead of an ul parent

- revert back to display block for list items to prevent unwanted behaviors
- fixes a handful of other linked issues (see main thread)
- updates docs to include more utilities for the one example

<label class="custom-file"><input type="file" class="custom-file-input" /><span class="custom-file-control"></span></label>
VS
<label class="custom-file"><input type="file" class="custom-file-input" /><span class="custom-file-control">test.txt</span></label>

* Fixed some linting issues

* Run npm tasks after scss cleanup

* Revert "Run npm tasks after scss cleanup"

This reverts commit 1103a0da.

* Property sort order for grid

* Let's respest the property order in the mixins

* Respect property sort order in reboot file

* ::-ms-expand is a vendor-prefix, add it to the scss-lint disable

* Revert hover mixin comment

* Fixed missing mixin hover-focus

fixes #17573

Despite now having the ability to override outline-variant color, it's not actually being used so each are still #fff

Related: https://github.com/twbs/bootstrap/pull/20734

— Moves print display utils to display utils file
— Removes all other .hidden- utils
— Expands on .invisible and it's mixin to provide options for visibility: visible and visibility: hidden

— Rename display docs page
— Move print display utils to display utils page
— Drop remaining of responsive utils page as it's being replaced with display utils
— Update nav to reflect changes

* Drop -x and -y as they're all the same
- Also move -width to elsewhere in the vars because it makes no sense by spacers.
- Update values of -x and -y across main Sass and docs Sass.
* Update docs to reflect changes; link to spacing utils from options page

Update Google sourcemap resources link

Based on this pen: http://codepen.io/zalog/pen/jyoyoR

In addition to #22011 and #21994

* Remove 'hover' from variable names
* Fix indentation in variables