Clarify that line() and polygon() include xy pixels

[radarhere]

Resolves #367

#6625 documented that ImageDraw's rectangle() included the endpoints. This continues that clarification of the documentation for line() and polygon().

As a demonstration, see the following code comparing the three functions.

from PIL import Image, ImageDraw

img = Image.new('RGB', (10, 10), (255, 255, 255))
draw = ImageDraw.Draw(img, 'RGBA')
draw.polygon([(2,2), (2, 8), (8,8), (8, 2)], fill=(0, 255, 0, 127))
draw.rectangle([(2,2), (8,8)], fill=(255, 0, 0, 127))
draw.line([(2,2), (8,8)], fill=(0, 0, 0, 255))

img.resize((200, 200), Image.NONE).save("out.png")

[hugovk]

Is this a bit clearer?

Suggested change

	The coordinate pixels are included in the drawn line.
	The endpoint coordinate pixels are included in the drawn line.

Or simply?

Suggested change

	The coordinate pixels are included in the drawn line.
	The endpoint pixels are included in the drawn line.

[radarhere]

Feel free to update it with any wording that you think is clearer, but both line() and polygon() accept a series of coordinates. I wonder if saying 'endpoint' implies it is only the first and last of those coordinates that are included?

[hugovk]

Hmm, good point. Not sure now! Let's stick with the original :)

[hugovk]

Suggested change

	coordinate. The coordinate pixels are included in the drawn polygon.
	coordinate. The endpoint coordinate pixels are included in the drawn polygon.

Suggested change

	coordinate. The coordinate pixels are included in the drawn polygon.
	coordinate. The endpoint pixels are included in the drawn polygon.