Fix functools.partialmethod docs and __all__

Doc/library/functools.rst

@@ -223,8 +223,8 @@ The :mod:`functools` module defines the following functions:
       ...         return self._alive
       ...     def set_state(self, state):
       ...         self._alive = bool(state)
-      ...     set_alive = partialmethod(set_alive, True)
-      ...     set_dead = partialmethod(set_alive, False)
+      ...     set_alive = partialmethod(set_state, True)
+      ...     set_dead = partialmethod(set_state, False)
       ...
       >>> c = Cell()
       >>> c.alive

Lib/functools.py

@@ -11,7 +11,7 @@
 
 __all__ = ['update_wrapper', 'wraps', 'WRAPPER_ASSIGNMENTS', 'WRAPPER_UPDATES',
            'total_ordering', 'cmp_to_key', 'lru_cache', 'reduce', 'partial',
-           'singledispatch']
+           'partialmethod', 'singledispatch']
 
 try:
     from _functools import reduce