gh-147965: Add shutdown() to multiprocessing.Queue excluded methods (GH-147970)

gh-147965: Add shutdown() to multiprocessing.Queue excluded methods (GH-147970)

The multiprocessing.Queue documentation states it implements all
methods of queue.Queue except task_done() and join(). Since
queue.Queue.shutdown() was added in Python 3.13,
multiprocessing.Queue also does not implement it. Update the docs
to include shutdown() in the list of excluded methods.