Prepare Tkinter 9.1 screenreader support

Feature or enhancement

Proposal:

Tcl/Tk adds support for screen-readers in Tk 9.1:
https://www.tcl-lang.org/software/tcltk/9.1.html

The related TIP 733 can be found here:
https://core.tcl-lang.org/tips/doc/trunk/tip/733.md

The C-Api documentation is provided at least here:
https://github.com/tcltk/tk/blob/main/doc/accessible.n

And the actual implementation is here:
https://github.com/tcltk/tk/blob/main/generic/tkAccessibility.c

Even though default values for standard widgets will be present custom widgets drawn by a Canvas can't be foreseen and a user might wish to alternate the defaults.
https://core.tcl-lang.org/tk/tktview/1110144ae9

Since tkinter is a thin wrapper around tk the appropriated API should be something like this:

def accessible(window, **kwargs):
    sub = [
        'role', 'name', 'description', 'value',
        'state', 'action', 'help string'
        ]
    parse = ()
    for cmd in sub:
        if val:= kwargs.pop(cmd, None):
            parse = parse + (cmd, val)
    if kwargs:
        raise ValueError
    window._tk.call('accessible', str(window), *parse)

Might best be placed into Misc.

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-153246
• gh-153247

Read TIP 733, Tk's accessible.n C-API documentation, and generic/tkAccessibility.c to understand the Tk 9.1 interface. Compare the proposed direction with linked PRs gh-153246 and gh-153247, then confirm the appropriate Tkinter API location, possibly Misc; done means custom Canvas widgets can provide or override accessibility values.