julia

5ae88f51 - improve `Union` docs as discused in discourse (#45109)

improve `Union` docs as discused in discourse (#45109) Co-authored-by: Viral B. Shah <ViralBShah@users.noreply.github.com> Co-authored-by: Daniel Karrasch <daniel.karrasch@posteo.de> Co-authored-by: Jameson Nash <vtjnash@gmail.com>