I'm not sure why I didn't bother to figure this out before now, because I know it was vaguely on my to-do list... but I had my hand forced when I migrated Memory Iota, the Emperor's soft canon blog, over to Grav. While I don't expect a lot of people actually give a shit about this blog, I know I have old links here and there, so it's nice to make sure those still work. Before I started digging into Grav, I thought I was going to have to handle it in my htaccess, but they really go out of their way to keep people from needing to touch that at all. So I could set up forwarding from the old urls to the new, or I could even have the site serve the pages at either url. I decided both here and on Iota that forwarding to the new correct url was best. It was a little tedious to set up because I had to go through page by page to do it the way they have it in their system, but now that it's done I'm happy to have finished it.