[3.12] gh-102856: Add changes related to PEP 701 in 3.12 What's New docs (GH-104824) (#104847)

gh-102856: Add changes related to PEP 701 in 3.12 What's New docs (GH-104824)
(cherry picked from commit c45701e9ef004a523ebb28f3be902b3cf2cf7a9b)

Co-authored-by: Marta Gómez Macías <mgmacias@google.com>
Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com>
Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>