ob: adding no-expand to list of header argument names

* lisp/ob.el (org-babel-header-arg-names): no-expand is now part of
  the default header argument names list.

lisp/ob.el

@@ -286,7 +286,7 @@ then run `org-babel-pop-to-session'."
 
 (defconst org-babel-header-arg-names
   '(cache cmdline colnames dir exports file noweb results
-	  session tangle var eval noeval comments)
+    session tangle var eval noeval comments no-expand)
   "Common header arguments used by org-babel.
 Note that individual languages may define their own language
 specific header arguments as well.")