[css-color-4][editorial] Small clarity improvements

Author: svgeesus

css-color-4/Overview.bs

@@ -5991,6 +5991,9 @@ Issue: add pseudocode for EdgeSeeker GMA
 	These two colors are then converted to 
 	the linear-light version of the target RGB space.
 
+	Because the gamut boundary is now an axis-aligned cube,
+	finding the intersection is faster.
+
 	A ray is cast from the inside of the RGB cube, 
 	from the anchor point to the current color. 
 	The intersection along this path