Fix host in address of socket.create_server example. (GH-17706)


Host as None in address raises TypeError since it should be string, bytes or bytearray.
(cherry picked from commit 43682f1e39a3c61f0e8a638b887bcdcbfef766c5)

Co-authored-by: Karthikeyan Singaravelan <tir.karthi@gmail.com>
diff --git a/Lib/socket.py b/Lib/socket.py
index 5b17906..f83f36d 100644
--- a/Lib/socket.py
+++ b/Lib/socket.py
@@ -843,7 +843,7 @@
     connections. When false it will explicitly disable this option on
     platforms that enable it by default (e.g. Linux).
 
-    >>> with create_server((None, 8000)) as server:
+    >>> with create_server(('', 8000)) as server:
     ...     while True:
     ...         conn, addr = server.accept()
     ...         # handle new connection