Use spinner component in JS

So, after giving it a look.

Autocomplete spinner and Ajax are not linked.

Ajax's one is generated in JS with JS theme functions.
Autocomplete is pure CSS.

In Bootstrap 3, as there are the glyphicons, it is possible to provide a default clean input group with an icon.

And what Bootstrap 3 does is that it removes Core CSS in its .info.yml and then override jQuery UI behavior to detect the glyphicon and adds a class to make it spin.

So, we would need to provide an empty input group (I am not ok with that) and then do like in https://git.drupalcode.org/project/bootstrap/-/blob/8.x-3.x/js/misc/auto... to set the spinner inside the content of this input group... So I guess there will be side effects with the width of the input group.

Let's keep it as it is and only override JS theme functions.

Automatically closed - issue fixed for 2 weeks with no activity.