Commit ec14d4ecb5 (builtin.h: take over documentation from
api-builtin.txt, 2017-08-02) deleted api-builtin.txt and moved the
contents into builtin.h, but new-command.txt still references the old
file.
Signed-off-by: Wes Lord <weslord@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>