Correct coderef switch in docstring

lisp/org-src.el

@@ -63,7 +63,7 @@ there are kept outside the narrowed region."
   "The default coderef format.
 This format string will be used to search for coderef labels in literal
 examples (EXAMPLE and SRC blocks).  The format can be overwritten in
-an individual literal example with the -f option, like
+an individual literal example with the -l option, like
 
 #+BEGIN_SRC pascal +n -r -l \"((%s))\"
 ...