tests/test-gendoc-fr.t

rust-cpython: move $leaked struct out of macro

It wasn't easy to hack the $leaked struct since errors in macro would
generate lots of compile errors. Let's make it a plain struct so we can
easily extend it.

PyLeakedRef keeps a more generic PyObject instead of the $name struct
since it no longer has to call any specific methods implemented by
the $name class. $leaked parameter in py_shared_iterator!() is kept
for future change.

#require docutils gettext

  $ $TESTDIR/check-gendoc fr
  checking for parse errors