gh-112205: Support @setter annotation from AC

[corona10]

• Issue: Support getters and setters in Argument Clinic #112205

[corona10]

@colesbury @erlend-aasland @AlexWaygood
The current implementation is not super pretty, so please leave feedback for this implementation.
I tried not to touch the overall architecture of AC as possible.

• Unify getter/setter method macro definition with undef keyword.
• Update AC to support @setter annotation.

[corona10]

For the dev guide, I will send a PR once the PR is landed.

[corona10]

And also, we need to consider supporting PyDoc for getter/setter with the separated PR.

cpython/Modules/_io/textio.c

Lines 181 to 186 in 384d6c1

	static PyGetSetDef textiobase_getset[] = {
	{"encoding", (getter)textiobase_encoding_get, NULL, textiobase_encoding_doc},
	{"newlines", (getter)textiobase_newlines_get, NULL, textiobase_newlines_doc},
	{"errors", (getter)textiobase_errors_get, NULL, textiobase_errors_doc},
	{NULL}
	};

[erlend-aasland]

Overall this looks good to me; thanks!

I would prefer to use a naming aligned with the names already used in the C API (tp_getset, PyGetSetDef); that is, consistently use getset and GETSET instead of getsetter and GETSETTER.

[erlend-aasland]

Oops, I probably introduced a typo with my recent suggestions; sorry 'bout that!

[corona10]

@erlend-aasland Thank you nice catch! PTAL one more time

[erlend-aasland]

LGTM. Let's wait for Alex to chime in.

(cc. @colesbury, if you'd like to take a look.)

[AlexWaygood]

(I'm travelling right now, but will do my best to review this tomorrow or Wednesday!)

[AlexWaygood]

Thanks! A few small suggestions, mostly to do with error messages:

[AlexWaygood]

LGTM, thanks!