gh-107704: Argument Clinic: add support for deprecating keyword use of parameters (GH-107984)

It is now possible to deprecate passing keyword arguments for
keyword-or-positional parameters with Argument Clinic, using the new
'/ [from X.Y]' syntax.
(To be read as "positional-only from Python version X.Y")

Co-authored-by: Erlend E. Aasland <erlend@python.org>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>