Add Scrollbar Customisation to docs

[EWZPraktikant]

Prerequisites

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

Proposal

Please make the documentation more clear on how to style Scrollbars.

You could add a Subheadline to https://getbootstrap.com/docs/5.3/utilities/overflow/ at the very end of the page that tells you how to style the scrollbar.

Motivation and context

I recently looked for a way to style my scrollbars with Bootstrap, but I couldn't find anything. Not even the search function in the documentation was giving me anything. Maybe I just didn't see it or missed it somehow, but all I could find was this: #37710

I think it could help others with the same problem, find a faster sollution then I did.

[julien-deramond]

Closing it as a duplicate of #31100. We'll double-check in v6 when we change our browser support whether it can be done.