A modifier class to inverse the behaviour of any spinner

Prerequisites

• I have searched for duplicate or closed feature requests
• I have read the contributing guidelines

Proposal

I suggest having a modifier class that whenever added to any spinner reverses its behavior, whether it is a small spinner, growing spinner, or border spinner. Adding this class to a spinner-border makes it rotate in the other direction, while adding it to a spinner-grow makes it shrink instead of growing.

Motivation and context

The issue https://github.com/twbs/bootstrap/issues/37989 was opened for a very similar feature request. Yet, it was closed as it only suggests one new base class, and just for the spinner-border. A discussion about it was in the related pull request https://github.com/twbs/bootstrap/pull/37990 where a modifier class for all spinners was suggested.