Merge reprioritization section with frame section

[martinthomson]

It's one paragraph that references the next paragraph. It doesn't need to stand alone.

[MikeBishop]

I was worried about losing the anchor, but it appears you've deleted the only reference to it.

[LPardue]

The current section layout was intentionally done in order to discombobulate the case of using PRIORITY_UPDATE for initial priority (see #1167 for context).

Now, you've also opened a related issue on #1722. I think the outcome of that influences what we might choose to do here.

[LPardue]

As an editorial suggestion, I'll decline this one as we didn't do anything on #1722.