In the "Force Push" warning modal dialog, indicate the number of affected branches

In the Force Push warning, it indicates that "one or more branch is selected for a force push".  It's very rare that I would ever force push more than one branch at once - in fact I can't remember ever doing it.  It would actually be beneficial to have a count of branches that are about to be force pushed. 

Telling me that 1 branch (or whatever I expect it to be) will be affected gives me confidence in what I'm about to do.  Telling me one or more makes me doubt what I'm about to do.