gh-65697: Improved error msg for configparser key validation (#135527)

* Improved error msg for configparser key validation and added note in 3.14 whatsnew

* Properly added change to configparser

* 📜🤖 Added by blurb_it.

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Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>

Jacob Austin Lincoln committed 10mo ago

81237fbcf6adc962647566eafca62dd5a905375e

Parent: 2bd3895

Committed by GitHub <noreply@github.com> on 6/15/2025, 4:13:19 PM