[css-sizing-3] Clarify that an automatic size is treated as no intrinsic dimension wrt aspect ratio calculations. #4637

Author: fantasai

css-sizing-4/Overview.bs

@@ -189,8 +189,9 @@ Intrinsic Aspect Ratios: the 'aspect-ratio' property</h3>
 	which will be used in the calculation of ''height/auto'' sizes
 	and some other layout functions.
 	The box’s <a>automatic sizes</a>
-	are then calculated the same as for
-	a <a>replaced element</a> with an <a>intrinsic aspect ratio</a>,
+	are calculated the same as for
+	a <a>replaced element</a> with an <a>intrinsic aspect ratio</a>
+	and no <a>intrinsic dimension</a> in that axis,
 	see e.g. <a href="https://www.w3.org/TR/CSS2/visudet.html">CSS2 &sect;&#x202F;10</a>
 	and <a href="https://www.w3.org/TR/css-flexbox-1/#algo-main-item">CSS Flexible Box Model Level 1 &sect;&#x202F;9.2</a>.
 	The axis in which the <a>preferred size</a> calculation