Remove incorrect imports rationale comment in `http.server` (#128278)

Remove reference to gethostbyaddr(), because it's not actually used within this code.

Lib/http/server.py

diff --git a/Lib/http/server.py b/Lib/http/server.py
index a6f7aec..a90c8d3 100644
--- a/Lib/http/server.py
+++ b/Lib/http/server.py
@@ -99,7 +99,7 @@
 import posixpath
 import select
 import shutil
-import socket # For gethostbyaddr()
+import socket
 import socketserver
 import sys
 import time