Use METH_NOARGS when no arguments are required

[radarhere]

This PR first replaces '1' with METH_VARARGS in various locations, improving clarity. Changing code like this -

Pillow/src/_imaging.c

Lines 3421 to 3425 in d393cfb

	static struct PyMethodDef methods[] = {
	/* Put commonly used methods first */
	{"getpixel", (PyCFunction)_getpixel, 1},
	{"putpixel", (PyCFunction)_putpixel, 1},

to match how it is specified elsewhere in Pillow -

Pillow/src/_imagingft.c

Lines 1228 to 1230 in d393cfb

	static PyMethodDef font_methods[] = {
	{"render", (PyCFunction)font_render, METH_VARARGS},
	{"getsize", (PyCFunction)font_getsize, METH_VARARGS},

Then, this PR resolves #5487. The issue identifies 7 functions where we can use METH_NOARGS when no arguments are being used, rather than always using METH_VARARGS. This update is similar to #4441

[hugovk]

Thanks!