Mention namespace browser in the changelog

Author: Bozhidar Batsov

CHANGELOG.md

@@ -16,6 +16,7 @@ simpler to gain understanding of what you're using.
 * New vars: `cider-to-nrepl-filename-function` and `cider-from-nrepl-filename-function`
 are used to translate filenames from/to the nREPL server (default Cygwin implementation provided).
 * Java classpath browser (`M-x cider-classpath`).
+* Clojure namespace browser (`M-x cider-browse-ns` and `M-x cider-browse-ns-all`).
 
 ### Changes