PEP 245: Fix broken link.

Author: oraluben

pep-0245.txt

@@ -438,7 +438,7 @@ extension to Python's syntax does not change any existing syntax
 in any backward incompatible way.
 
 The new ``from __future__`` Python syntax (:pep:`236`), and the new warning
-framework (:pep:`236`) is ideal for resolving this backward
+framework (:pep:`230`) is ideal for resolving this backward
 incompatibility.  To use interface syntax now, a developer could
 use the statement::