On the Community Forums it was suggested I write a ticket for this, so here it is:

I found a "Format To Guidelines" option in the contextual menu of the commit message box. I thought that might be a handy way to format my commit messages with autowrap to the guideline bar (currently at 72 characters).

So far, I haven't gotten the option to do anything.

This brings up a bunch of questions:

1. Is it supposed to operate on the entire text of the buffer?
2. Is it supposed to just work on selected text?
3. Is it a toggle?  If so, there's no check mark in the contextual menu to indicate whether it's off or on.

In any case, no matter what I've tried to do (including the list above), I haven't seen the option do anything.