Rewording in Tooltips and Popover Docs

Created by: LarryAzevedo

On both https://getbootstrap.com/docs/4.1/components/popovers/#overview and https://getbootstrap.com/docs/4.1/components/tooltips/#overview, consider rewording:

Use white-space: nowrap; on your <a>s to avoid this behavior.

to

Use .text-nowrap on your <a>s to avoid this behavior.