Add codly-example?

[swaits]

I think having something like this available in codly's public interface could be quite nice. Or, it may deserve its own package.

I know I could've used this so many times in docs. Instead, I'm always hacking around with TWO copies of the example code (one for the listing, one for rendered), and I never really bother to make it look nice like you're doing.

[swaits]

@Dherse on further reflection, this merits its own package. I may take a stab at it, starting with your code. Cool?