[racket-dev] macros for sub-keywords

We've brought this up on this list before -- forms like provide export
their sub-keywords as macros.  I believe this is why the following
module compiles:

#lang racket
(require scribble/base)
(define (defn t) (bold t))
(provide all-defined-out)

Someone just spent 30 minutes wrestling with this.  When I finally
showed the problem, I was asked, "Wait, so why wasn't this just an
error?"

This is absurdly hard to diagnose and debug if you don't already know
quite a bit about what's going on.

Shriram