bpo-28146: Fix a confusing error message in str.format() (GH-24213)

Automerge-Triggered-By: GH:pitrou
(cherry picked from commit 4aeee0b47b3a2b604bbac37040320ffc88c291f2)

Co-authored-by: Irit Katriel <iritkatriel@yahoo.com>

Miss Islington (bot) committed 4y ago

2d780237d95cd3d95401f52be2edeac8b458eb68

Parent: c4c3beb

Committed by GitHub <noreply@github.com> on 5/13/2021, 9:24:49 PM