Use new functionality in spec middleware to retrieve spec info added in info middleware

[jpmonettas]

Now that we have spec-form in spec middleware with functionality to retrieve enhanced descriptions of spec, use that when collecting fns specs information since its our enhanced version of (s/form) that also supports multi-specs.

It's seams we will have to change around https://github.com/clojure-emacs/cider-nrepl/blob/master/src/cider/nrepl/middleware/util/meta.clj#L36

to use https://github.com/clojure-emacs/cider-nrepl/blob/master/src/cider/nrepl/middleware/spec.clj#L70
instead of s/form.