Evaling an erroring form into a comment

[RickMoynihan]

Evaling the form (throw (ex-info "foo" {})) with M-x cider-pprint-eval-last-sexp-to-comment yields the empty comment string:

;; =>

Arguably it should either:

1. Not yield a ;; => at all (just the empty string) (and appropriate cider error buffer)

or it should:

2. Print the error in the comment.

The later might be useful when describing code interactions and REPL sessions; though I think the former might be a more sensible default for normal usage.