gh-95913: Move py.exe to appropriate What's New section & refine text (#97718)

* Move Windows py.exe improvements from Typing section to New Features

* Add ref target label and use literal for py.exe

* Be clearer/explict about what legacy version arg components reprisent

* Apply other minor clarity and textual fixes to py.exe launcher text

* Refine phrasing of legacy sentence of py.exe desc

Co-authored-by: Ezio Melotti <ezio.melotti@gmail.com>

Co-authored-by: Ezio Melotti <ezio.melotti@gmail.com>