bpo-45391: mark UnionType as a class in documentation (GH-28757)


Signed-off-by: Bernát Gábor <bgabor8@bloomberg.net>
(cherry picked from commit e2cfc89e099b8fad5d8d5bd7f59dadffb6078778)

Co-authored-by: Bernát Gábor <gaborjbernat@gmail.com>
1 file changed