Added spacing to make it easier to work with the document.
Also, I keep doing that thing with the SNES where I put "SPC700" but really should just put "SNES". Bad habit. (The real reason for the commit.)
The idea: list all the systems shown in the "new file" dialog, link to their chips.
Also, moved all the important info out of genesis.md and removed it, finally!
Also also, fixed the tiniest issue in the credits. 😊