Update the OMG link (GH-30383)

(cherry picked from commit 04215a4272)

Co-authored-by: David Gilbertson <gilbertson.david@gmail.com>

Co-authored-by: David Gilbertson <gilbertson.david@gmail.com>

Doc/library/xml.dom.rst

@@ -73,7 +73,7 @@ implementations are free to support the strict mapping from IDL).  See section
    `Document Object Model (DOM) Level 1 Specification <https://www.w3.org/TR/REC-DOM-Level-1/>`_
       The W3C recommendation for the DOM supported by :mod:`xml.dom.minidom`.
 
-   `Python Language Mapping Specification <http://www.omg.org/cgi-bin/doc?formal/02-11-05.pdf>`_
+   `Python Language Mapping Specification <https://www.omg.org/spec/PYTH/1.2/PDF>`_
       This specifies the mapping from OMG IDL to Python.