[css-images-3] Clarify that 'crisp-edges' is appropriate for non-pixellated lineart.

Author: tabatkins

css-images-3/Overview.bs

@@ -1658,7 +1658,7 @@ Determining How To Scale an Image: the 'image-rendering' property {#the-image-re
 		<dd>
 			The image must be scaled with an algorithm that preserves contrast and edges in the image,
 			and which does not smooth colors or introduce blur to the image in the process.
-			This is intended for images such as pixel art.
+			This is intended for images such as pixel art or line drawings.
 
 		<dt><dfn>pixelated</dfn>
 		<dd>