Please update the sprite docs re: custom drawing

Every so often (couple of days) someone comes into the discord asking why their custom drawing function isn't being called, and it's because they're not setting the sprite's size. I believe that they're not setting it because the docs don't mention that draw won't be called if the sprite's size hasn't been set. The docs should mention this.


I'll file an issue on this - thanks for the suggestion!


Thank you very much! <3