gh-112205: Update textio module to use @getter as possible.

[corona10]

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

[corona10]

cpython/Modules/_io/textio.c

Lines 181 to 186 in 384d6c1

	staticPyGetSetDeftextiobase_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}
	};

Will be updated with separate PR: Need AC changes :)