Issue #23254: Document how to close the TCPServer listening socket.

Patch from Martin Panter.

diff --cc Misc/NEWS
index 30045398531338cd1f24cab2a1b25579a4e1b07c,9f3ca11daf4eacd77f38dbbb8e7741864c14c478..785d11cd475e8aedfd41e2625bfa1d1322230203
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -13,8 -13,10 +13,11 @@@ Core and Builtin
  Library
  -------
  
 -- Issue #19450: Update Windows builds to use SQLite 3.8.11.0
+ - Issue #23254: Document how to close the TCPServer listening socket.
+   Patch from Martin Panter.
+ 
 +- Issue #23426: run_setup was broken in distutils.
 +  Patch from Alexander Belopolsky.
  
  - Issue #17527: Add PATCH to wsgiref.validator. Patch from Luca Sbardella.