#16484: Change PYTHONDOCS to "https:", and fix links to use lowercase

Implementation by Sean Rodman; test by Kaushik Nadikuditi.
diff --git a/Doc/library/pydoc.rst b/Doc/library/pydoc.rst
index 743769f..57521f7 100644
--- a/Doc/library/pydoc.rst
+++ b/Doc/library/pydoc.rst
@@ -80,7 +80,7 @@
 Python interpreter and typed ``import spam``.
 
 Module docs for core modules are assumed to reside in
-http://docs.python.org/library/.  This can be overridden by setting the
+https://docs.python.org/library/.  This can be overridden by setting the
 :envvar:`PYTHONDOCS` environment variable to a different URL or to a local
 directory containing the Library Reference Manual pages.