Description of the new feature/enhancement

Text Ranges can be explored via a number of ways:

• Character
• Format
• Word
• Line
• Paragraph
• Page
• Document

We don't necessarily have to support all of them (refer to #3161 for us adding word navigation). But it would be interesting if we supported "format".

I envision us being able to jump between runs of formatted text. Today, the main formatting I can think of is colored text composed of foreground and background color. Maybe we could just see if any have changed and, if that's the case, that would be a breakpoint for formatted text navigation.

Proposed technical implementation details (optional)

Coincidentally, I just did a little bit of work in the AttrRowIterator. If that's actually taking a look at the text attributes, this would be an integral part of this design.