add text-default or maybe text-reset?

Created by: ShaunR

All the text-helpers are great but we don't have one that will reset the text color back to the default. This could be useful in places were we set all text color to text-danger but only want a single word or a single section to be the default color.

.text-default seams like a good name for this

Example

<div class="alert alert-danger">
   <p>I really want the word <span class="text-default">default</span> to be set back to the default color</p>
</div>