update doxs to use a Configurator context manager

Steve Piercy

2017-07-04 d91e5d4d5d0165a7f7599c84c988b981b5fd0d2d

 docs/narr/helloworld.py

@@ -7,10 +7,9 @@
    return Response('Hello %(name)s!' % request.matchdict)

if __name__ == '__main__':
    config = Configurator()
    config.add_route('hello', '/hello/{name}')
    config.add_view(hello_world, route_name='hello')
    app = config.make_wsgi_app()
    with Configurator() as config:
        config.add_route('hello', '/hello/{name}')
        config.add_view(hello_world, route_name='hello')
        app = config.make_wsgi_app()
    server = make_server('0.0.0.0', 8080, app)
    server.serve_forever()