Actions vs Links inside of Dropdowns

Created by: langdonx

With the idea that cursors now convey meaning (https://github.com/twbs/bootstrap/pull/21812), the dropdown documentation seems to need some love. The examples in the documentation refer to "actions" and "links", but each dropdown-item is just ultimately just an anchor (a link).

I'd be happy to submit a PR to improve the documentation (using a for links and button for actions with a small paragraph describing intent).