[docs] http.server.HTTPServer lacks member documentation

[Jonas Thiem]

http.server.HTTPServer appears to lack member documentation, most
notably the function "serve_forever" and the proper shutdown functions
to stop serving and close all open sockets (which I recall exist, but
which aren't documented in the class description although they should
be).

URL of the expected place of such documentation:
https://docs.python.org/3/library/http.server.html#http.server.HTTPServer

As you can see, the class HTTPServer is there but the members are
strangely left out - I suggest this should be fixed