[nerd] rate iTunes songs without mousing!

I like working from the keyboard as much as possible on my Mac, and once I started using iTunes' ratings more, it bothered me that I couldn't set them without using the mouse. Now I can! This is kind of fiddly, but doesn't require any special mastery of your Mac.

The solution mostly came from here, but that's structured in an unhelpful way, so here's my attempt at complete instructions:

( Seriously, this makes me unreasonably pleased. )