Backport "Add an infix shorthand for `Tuple.{Append, Concat}`" to 3.6#21962

WojciechMazur merged 2 commits intorelease-3.6.2scala/scala3:release-3.6.2from

release-3.6.2-backport-21288scala/scala3:release-3.6.2-backport-21288Copy head branch name to clipboard