Consider making .tooltip('show') throw an error when the target is `display: none`

Created by: cvrebert

This would allow us to drop a callout from the tooltip & popover docs and make the mistake more obvious to our users.

The current callout:

Don't try to show tooltips on hidden elements

Invoking $(...).tooltip('show') when the target element is display: none; will cause the tooltip to be incorrectly positioned.