.text-bold Class(es)

[codysherman]

While .text-bold seems like an obvious addition after adding .text-italic in Frow 3.3, there's actually a bit more complexity there with how to handle what the class should do.

Is the correct default behavior to add font-weight: bold, or is it font-weight: bolder. Should .text-bolder and .text-lighter exist?

I did not create .text-oblique when including .text-italic as I didn't see the need. The bold classes need the same evaluation.