List.rotate returns a Seq since Rakudo 2020.06
List.rotate returns a Seq since Rakudo 2020.06

ref #3495

While here flesh out a bit the routine description and adopt a more
common example style.

MasterDuke17/doc,MasterDuke17/doc,MasterDuke17/doc,tbrowder/doc,MasterDuke17/doc,tbrowder/doc,tbrowder/doc,tbrowder/doc