Improve a bit the handling and display of clojure-mode-version.

`clojure-mode-version` is better off being a variable and it's nice to have an interactive function to display it. Most modes add a reference to a function such as `clojure-mode-display-version` in their menus.

Author: Bozhidar Batsov

clojure-mode.el

@@ -365,9 +365,13 @@ numbers count from the end:
  leiningen.compile -> leiningen.test.compile (uses 1)
  clojure.http.client -> clojure.http.test.client (uses -1)")
 
-(defun clojure-mode-version ()
- "Currently package.el doesn't support prerelease version numbers."
- "2.0.0")
+(defvar clojure-mode-version "2.0.0"
+ "The current version of `clojure-mode'.")
+
+(defun clojure-mode-display-version ()
+ "Display the current `clojure-mode-version' in the minibuffer."
+ (interactive)
+ (message "clojure-mode (version %s)" clojure-mode-version))
 
 ;; For compatibility with Emacs < 24, derive conditionally
 (defalias 'clojure-parent-mode