"Modifying" an old commit by checking it out, --amend'ing it, then
rebasing on top of it, is a slightly cumbersome technique, but I've
found it useful frequently enough to make it seem worth documenting.
Signed-off-by: N"J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: NJunio C Hamano <junkio@cox.net>