By default, check-ignore does not list tracked files at all since
they are not subject to ignore patterns.
Make this clearer in the man page.
Reported-by: Guilherme <guibufolo@gmail.com> Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>