Merge branch 'jc/checkout-detach-wo-tracking-report'

"git checkout/switch --detach foo", after switching to the detached HEAD state, gave the tracking information for the 'foo' branch, which was pointless. Tested-by: M Hickford <mirth.hickford@gmail.com> cf. <CAGJzqsmE9FDEBn=u3ge4LA3ha4fDbm4OWiuUbMaztwjELBd7ug@mail.gmail.com> * jc/checkout-detach-wo-tracking-report: checkout: omit "tracking" information on a detached HEAD