[3.12] gh-69001: Replace maintainer email in IDLE credits (GH-129588) (#129714)

Instead, anyone requesting credit should submit a PR with contribution summary.
(Also fix typo in existing name.)
(cherry picked from commit 76e018294801ab95f30756c702b63bf6b4c23310)

Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com>