Doc: Fix inconsistency in multiprocessing (GH-12273)

Doc/library/multiprocessing.rst

@@ -1654,7 +1654,7 @@ their parent process exits.  The manager classes are defined in the
       Connect a local manager object to a remote manager process::
 
       >>> from multiprocessing.managers import BaseManager
-      >>> m = BaseManager(address=('127.0.0.1', 5000), authkey=b'abc')
+      >>> m = BaseManager(address=('127.0.0.1', 50000), authkey=b'abc')
       >>> m.connect()
 
    .. method:: shutdown()