Align type_declaration with parsetree.

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/extension_points@13445 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Align exception_declaration with Parsetree.

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/extension_points@13446 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02