Update special form completion candidates

This uses the same set as tools.analyzer.js - see [here](https://github.com/clojure/tools.analyzer.js/blob/master/src/main/clojure/clojure/tools/analyzer/js.clj#L46) and [here](https://github.com/clojure/tools.analyzer/blob/master/src/main/clojure/clojure/tools/analyzer.clj#L228). This is the same as [cljs.analyzer](https://github.com/clojure/clojurescript/blob/master/src/clj/cljs/analyzer.clj#L382), but with `catch` and `finally` included.