t6426: fix TODO about making test more comprehensive
t6426.7 (a rename/add testcase) long had a TODO/FIXME comment about
how the test could be improved (with some commented out sample code
that had a few small errors), but those improvements were blocked on
other changes still in progress. The necessary changes were put in
place years ago but the comment was forgotten. Remove and fix the
commented out code section and finally remove the big TODO/FIXME
comment.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>