Document the "Morph" generator setting somewhere

[gbirchmeier]

I'm a noob to this one (though not ALttP:R), and I could not figure out what the "Morph: [Randomized/Vanilla]" setting meant on the generator page.

Could you add a section to the docs about this page's configuration options? Or better yet, just put a little explainer on the form itself?

(I ended up getting my question answered on Reddit.)

[gbirchmeier]

I'd offer a PR to add some help to the form, but I wasn't able to find the form view in the repo. I suspect it's not actually in here.