Old-style property accessor raises warning on compile

clojure.browser.repl is accessing the property of an event via the / syntax, which seems to have been deprecated:
https://github.com/clojure/clojurescript/blob/f74b50967ef4041db585bd6c6f2f490285f61961/src/cljs/clojure/browser/repl.cljs#L71

It causes warnings on compile:

WARNING: No such namespace: e at line 71 resources/public/js/bin-debug/clojure/browser/repl.cljs

Attached is a fix