SF bug #1119700: list extend() accepts args besides lists

Doc/lib/libstdtypes.tex

@@ -1075,7 +1075,7 @@ Notes:
   no longer works in Python 2.0.  Use of this misfeature has been
   deprecated since Python 1.4.
 
-\item[(3)] Raises an exception when \var{x} is not a list object.
+\item[(3)] \var{x} can be any iterable object.
 
 \item[(4)] Raises \exception{ValueError} when \var{x} is not found in
   \var{s}. When a negative index is passed as the second or third parameter