[css-overflow-3] Make note slightly more precise wrt floats. w3c#7511

Author: fantasai

css-overflow-3/Overview.bs

@@ -269,12 +269,12 @@ Scrollable Overflow</h3>
 			Note: This padding represents,
 			within the [=scrollable overflow rectangle=],
 			the box’s own padding
-			so that when its in-flow content is scrolled to the end,
-			there is padding between the end-edge of its content
+			so that when its content is scrolled to the end,
+			there is padding between the end-edge of its in-flow or floated content
 			and the border edge of the box.
 			It typically ends up being exactly the same size as the box's own padding,
 			except in a few cases--
-			such as when an out-of-flow element,
+			such as when an out-of-flow positioned element,
 			or the visible overflow of a descendent,
 			has already increased the size of the [=scrollable overflow rectangle=]
 			outside the conceptual “content edge” of the [=scroll container=]’s content.