Whoops, I thought you were talking about the site title this whole time 🙂
I did a ton of searches, and the only thing I can see is how to add or remove page titles…..but I haven’t seen anything that explains how to edit the page title in the way you need. I’m pretty sure this can be done, but I have no idea how. You’ll probably want to head over to the SP forum to see if one of the devs may know how to do this. If I come across anything I’ll post it here.