js detection - refinements

[vemv]

A possible refinements for https://github.com/clojure-emacs/clj-suitable/pull/36 that I thought of:

• If any element within the -> chain starts with ., then consider that the operand is js, not cljs, no matter what
• use cider.nrepl.middleware.util.cljs/grab-cljs-env for checking if a given symbol corresponds to a js ("string") require