[racket-dev] raco pkg remove needs to state package dependencies

I tried the following:


128-110-72-21:ragg dyoo$ ~/local/racket/bin/raco pkg remove ragg
raco pkg remove: cannot remove packages that are dependencies of other packages
  dependencies:
   ragg

The error message needs to say which package is depending on what
other packages.  Otherwise, the user is forced to manually search for
which package is causing the problem.