org-agenda.el (org-agenda-dim-blocked-tasks): Fix typo.

* org-agenda.el (org-agenda-dim-blocked-tasks): Fix typo.

Thanks to Paul Eggert for spotting this and fixing it in Emacs trunk.

lisp/org-agenda.el

@@ -821,7 +821,7 @@ will only be dimmed."
   :group 'org-agenda-todo-list
   :type '(choice
 	  (const :tag "Do not dim" nil)
-	  (const :tag "Dim to a grey face" t)
+	  (const :tag "Dim to a gray face" t)
 	  (const :tag "Make invisible" invisible)))
 
 (defcustom org-timeline-show-empty-dates 3