recommend requests library (closes #23989)

Patch by Van Lindberg.
diff --git a/Doc/library/urllib.rst b/Doc/library/urllib.rst
index b2a817d..d0cc548 100644
--- a/Doc/library/urllib.rst
+++ b/Doc/library/urllib.rst
@@ -24,6 +24,11 @@
 instead of filenames.  Some restrictions apply --- it can only open URLs for
 reading, and no seek operations are available.
 
+.. seealso::
+
+    The `Requests package <http://requests.readthedocs.org/>`_
+    is recommended for a higher-level http client interface.
+
 .. warning:: When opening HTTPS URLs, it does not attempt to validate the
    server certificate.  Use at your own risk!