[racket] documentation example for slideshow/pict

> That sounds great, and I'm sure one of the Pict
> experts could write better examples than mine.

Yes, but still, upload your code to the cookbook.

> But please look at the
> slideshow & the keybinding dox in 3.3.8 Defining Custom Shortcuts.
> See if you think if there's enough examples.  I know I floundered.

It's not bad, really.  It could probably be better for supporting
complex examples, but it seems a pretty low-priority compared to the
real pain points.  The assumption is probably that anyone who can
actually make and run those edits can also follow the docs of a class
system.

Shriram