git.txt: list index versions in plain English At the first look, a user may think the default version is "23". Even with UNIX background, there's no reference anywhere close that may indicate this is glob or regex. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>