Within the help message of 'git add -i', the 'diff' command uses one
tab character and blanks to create the space between the name and the
description while the others use blanks only. So if the tab size is
not at 4 characters, this description will not be in range.
Replace the tab character with blanks.
Signed-off-by: Ralf Thielow <ralf.thielow@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>