bpo-33187: Document 3.9 changes to xml.etree.ElementInclude.include (GH-20438)


Looks like the merging of bpo-33187 and bpo-20928 was racy, resulting in
this change going undocumented.
(cherry picked from commit 301f0d4ff9b6bd60599eea0612904f65a92e6dd9)

Co-authored-by: Shantanu <hauntsaninja@users.noreply.github.com>
1 file changed