fix error message

Author: fogus

src/main/clojure/clojure/core/async.clj

@@ -190,7 +190,7 @@ the following values:
   "takes a val from port. Must be called inside a (go ...) block. Will
   return nil if closed. Will park if nothing is available."
   [port]
-  (assert nil ">! used not in (go ...) block"))
+  (assert nil "<! used not in (go ...) block"))
 
 (defn take!
   "Asynchronously takes a val from port, passing to fn1. Will pass nil