[css-sizing] Defer sizing of replaced elements to CSS2.1 algorithms, …

…since the one here isn't quite correct. Addresses #794.

css-sizing-3/Overview.bs

@@ -365,27 +365,17 @@ Intrinsic Size Determination</h2>
 		<dfn export>Intrinsic sizing</dfn> determines sizes based on the contents of an element,
 		without regard for its context.
 
+<h3 id='intrinsic-sizes'>
+Intrinsic Sizes</h3>
 
-<h3 id='replaced-intrinsic'>
-Intrinsic Sizes of Replaced Elements</h3>
-
-	<p>
-		For replaced elements,
-		the <a>min-content size</a> and <a>max-content size</a> are equivalent
-		and correspond to the appropriate dimension of the concrete object size returned by
-		the <a href="https://www.w3.org/TR/css3-images/#default-sizing">default sizing algorithm</a> [[!CSS3-IMAGES]]
-		of the element,
-		calculated with an unconstrained specified size.
-
-<h3 id='inline-intrinsic'>
-Intrinsic Sizes of Other Boxes</h3>
-
-	The <a>min-content size</a> of a box is the size it would have as an
-	''width/auto''-sized float in a zero-sized containing block.
+	The <a>min-content size</a> of a box in each axis
+	is the size it would have as an
+	''width/auto''-sized (in that axis) float in a zero-sized containing block.
 	(In other words, the minimum size it has when sized as “shrink-to-fit”.)
 
-	The <a>max-content size</a> of a box is the size it would have as an
-	''width/auto''-sized float in an infinitely-sized containing block.
+	The <a>max-content size</a> of a box in each axis
+	is the size it would have as an
+	''width/auto''-sized (in that axis) float in an infinitely-sized containing block.
 	(In other words, the maximum size it has when sized as “shrink-to-fit”.)
 
 	Note: This specification does not define how to determine these sizes.
@@ -394,6 +384,8 @@ Intrinsic Sizes of Other Boxes</h3>
 	and/or existing implementations
 	for further details.
 
+	Issue: Intrinsic sizes of images without an intrinsic size are weird and undefined, and should probably get some love
+
 <h3 id="intrinsic-contribution">
 Intrinsic Contributions</h3>