Small edits

Just some small edits i noticed or were pointed out to me. I expanded the Brushes section a bit to hopefully make it a little clearer as to when and why you would give one to another player (or, also, on yourself).

Also added acknowledgements Abe Mendez (@abemendez & abemendes.itch.io) and Caro Asercion (@SeaExcursion & seaexcursion.itch.io), who's conversations really got these gears turning! If you like the stuff going on in GMless you should 100% check out their work.