Fix org-indent-mode message when mode is refused

* lisp/org-indent.el (org-indent-mode): Fix grammar for message when mode is refused

lisp/org-indent.el

@@ -135,11 +135,11 @@ FIXME:  How to update when broken?"
    ((org-bound-and-true-p org-inhibit-startup)
     (setq org-indent-mode nil))
    ((and org-indent-mode (featurep 'xemacs))
-    (message "org-indent-mode does not work in XEmacs - refused to turn it on")
+    (message "org-indent-mode does not work in XEmacs - refusing to turn it on")
     (setq org-indent-mode nil))
    ((and org-indent-mode
 	 (not (org-version-check "23.1.50" "Org Indent mode" :predicate)))
-    (message "org-indent-mode is can crash Emacs 23.1 - refused to turn it on!")
+    (message "org-indent-mode can crash Emacs 23.1 - refusing to turn it on!")
     (ding)
     (sit-for 1)
     (setq org-indent-mode nil))