Link to external documentation about new style classes was

wrong. Fix issue 1774.

Doc/ref/ref3.tex

@@ -25,7 +25,7 @@ object's type, under certain controlled conditions.  Until this manual
 undergoes extensive revision, it must now be taken as authoritative
 only regarding ``classic classes'', that are still the default, for
 compatibility purposes, in Python 2.2 and 2.3.  For more information,
-see \url{http://www.python.org/doc/newstyle.html}.}
+see \url{http://www.python.org/doc/newstyle/}.}
 An object's type determines the operations that the object
 supports (e.g., ``does it have a length?'') and also defines the
 possible values for objects of that type.  The
@@ -1101,7 +1101,7 @@ implemented before for compatibility concerns, like the method resolution order
 in case of multiple inheritance.
 
 This manual is not up-to-date with respect to new-style classes.  For now,
-please see \url{http://www.python.org/doc/newstyle.html} for more information.
+please see \url{http://www.python.org/doc/newstyle/} for more information.
 
 The plan is to eventually drop old-style classes, leaving only the semantics of
 new-style classes.  This change will probably only be feasible in Python 3.0.