* Change it's to its.

* Fix links

* Fix typos

Close #21090 - Fix aria-pressed attribute for buttons in container with data-attribute="buttons"

Custom Forms: Allow Chrome/Firefox feature that lets the user drag and drop into file inputs (#20033)

* Restored functionality of dragging files into .custom-file inputs.

* Replaced padding with height on .custom-file-input

Tried redoing this in flexbox, but it falls apart really quickly. Any changes in height of the cells throws it all off since the rows become columns (and thus, content across columns cannot be equally sized). Rather than implement something with such glaring flaws, I'm nuking it outright.

* Close dropdown menu when focusing an outside element
* Update unit test to new markup