changelog: new rules, other minor updates

Hi folks!

I've updated the PDF file you can download - it's pretty much exactly the same, except:

• The formatting is slightly different (each section starts on a new page).
• It's clearer from the beginning that you need to include both jokers in your pack of cards (thank you Dec & Bibby for pointing out that oversight!).
• I've clarified some of the rules in The Edification, removing potentially confusing and superfluous phrases.
• I've added a new rule which handles what happens if, in The Edification, the builder places a joker on top of a joker. Thank you to irene for pointing out that oversight, which they had the (mis)fortune to encounter in their first game!

Also, as a footnote, thank you so much to everyone who has played, bought, and talked about the game so far! There is nothing more heartening than to see people appreciate your work and I've had a good warm glow these past two weeks since I released it.

- Charlie