Change actor.__ray_kill__() to ray.kill(actor) (#7360)

doc/source/actors.rst

@@ -147,7 +147,7 @@ collected. The ``ObjectID`` resulting from the task can be waited on to wait
 for the actor to exit (calling ``ray.get()`` on it will raise a ``RayActorError``).
 Note that this method of termination will wait until any previously submitted
 tasks finish executing. If you want to terminate an actor immediately, you can
-call ``actor_handle.__ray_kill__()``. This will cause the actor to exit immediately
+call ``ray.kill(actor_handle)``. This will cause the actor to exit immediately
 and any pending tasks to fail. Any exit handlers installed in the actor using
 ``atexit`` will be called.
 

doc/source/package-ref.rst

@@ -13,6 +13,8 @@ Ray Package Reference
 
 .. autofunction:: ray.put
 
+.. autofunction:: ray.kill
+
 .. autofunction:: ray.get_gpu_ids
 
 .. autofunction:: ray.get_resource_ids