Need confirmation of a Revert

Now that we have our shiny new Revert tool, we need a small enhancement to the interaction, because it's a bit unclear whether or not the reversion has actually happened (unless you know to scroll down and check the history).

So, when you're looking at a previous version, you can see the option to Revert via the submit button at the top. If you press it, we need a confirmation note on the screen you see after that, when you're looking at the completed reversion.

I'd like it to be one of those slide-y confirmation messages that slides up "under" the navigation bar, like the ones we began using in the sign up process.

I'll attached a mock for reference.