Fixed typo in docstring.

lisp/org-clock.el

@@ -207,7 +207,7 @@ of a different task.")
 (defun org-clock-in (&optional select)
   "Start the clock on the current item.
 If necessary, clock-out of the currently active clock.
-With prefix arg SELECT, offer a list of recently clocked ta sks to
+With prefix arg SELECT, offer a list of recently clocked tasks to
 clock into.  When SELECT is `C-u C-u', clock into the current task and mark
 is as the default task, a special task that will always be offered in
 the clocking selection, associated with the letter `d'."