use zip for cleaner iteration with 1-based index

[xtqqczze]

No description provided.

[sylvestre]

if you cherry-pick my changes, please keep the author ...

[github-actions]

GNU testsuite comparison:

Note: The gnu test tests/seq/seq-epipe is now being skipped but was previously passing.
Congrats! The gnu test tests/tail/tail-n0f is now passing!

[xtqqczze]

if you cherry-pick my changes, please keep the author ...

I may be mistaken, but I don’t believe this would be considered a cherry-pick, since it also includes additional changes to dircolors. I also didn’t think there were any attribution concerns, as I had originally made the suggestion in the referenced discussion (#10647 (comment)).

[sylvestre]

still disagree ...

[xtqqczze]

rebased to cherry-pick from #10647 (comment)

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/date/resolution. tests/date/resolution is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/head/head-write-error. tests/head/head-write-error is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/tail/retry. tests/tail/retry is passing on 'main'. Maybe you have to rebase?
Skipping an intermittent issue tests/pr/bounded-memory (passes in this run but fails in the 'main' branch)