git-config: document interactive.singlekey requires Term::ReadKey
git-config: document interactive.singlekey requires Term::ReadKey

Most distributions don't require Term::ReadKey as dependency, leaving
the user to wonder why the setting doesn't work.

Signed-off-by: Simon Ruderich <088e16a1019277b15d58faf0541e11910eb756f6@ruderich.org>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git