bpo-34576 - Fix the formatting for security considerations in http.server.rst (#10005)

* bpo-34576 - Fix the formatting for security considerations in http.server.rst

* Address review comment.

Doc/library/http.server.rst

@@ -16,12 +16,12 @@
 
 This module defines classes for implementing HTTP servers (Web servers).
 
-Security Considerations
------------------------
 
-http.server is meant for demo purposes and does not implement the stringent
-security checks needed of real HTTP server. We do not recommend
-using this module directly in production.
+.. warning::
+
+    :mod:`http.server` is meant for demo purposes and does not implement the
+    stringent security checks needed of a real HTTP server. We do not recommend
+    using this module directly in production.
 
 
 One class, :class:`HTTPServer`, is a :class:`socketserver.TCPServer` subclass.