Make Python parameters types hyperlinks in the doc strings.

It is very useful to be able to click on the parameter types in a function
documentation to go to this parameter description, so always use hyperlink
markup for the parameters of class types, even if not all of them are
necessarily documented -- Sphinx doesn't seem to complain about links to
unknown classes.

Examples/test-suite/python/doxygen_basic_translate_runme.py

@@ -71,7 +71,7 @@ commentVerifier.check(doxygen_basic_translate.function7.__doc__,
     """
     Test for a parameter with difficult type
     (mostly for python)
-    :type a: Shape
+    :type a: :py:class:`Shape`
     :param a: Very strange param
     """
 )