[doc] fix minor typo for argparse (GH-28451)

"A JSONDecodeError" instead of "An JSONDecodeError".
(cherry picked from commit db0133f98dd42d0fb82a7675bde175cec51bb860)

Co-authored-by: Louis Sautier <sautier.louis@gmail.com>

Miss Islington (bot) committed 4y ago

6d604494564e86436da207cc5ebd3d6823db988d

Parent: fd52afd

Committed by GitHub <noreply@github.com> on 9/28/2021, 2:07:13 PM