[css-writing-modes] Clarify fill-available fit clause for <http://www.w3.org/mid/b12929ef85504669fd6c780010cef743@gtalbot.org>

Author: fantasai

css-writing-modes/Overview.bs

@@ -2048,11 +2048,11 @@ Auto-sizing Block Containers in Orthogonal Flows</h4>
         <dd>the <a href="http://www.w3.org/TR/css3-sizing/#max-content-measure">max-content inline-size</a> of the box
 
         <dt><var>constraint</var>
-        <dd>the box’s <i>inline-axis</i> <a href="http://www.w3.org/TR/css3-sizing/#terms">fill-available fit</a>
-        into the smaller of
+        <dd>the <i>inline-axis</i> size
+        that would match the box's <i>inline-axis</i> outer edges to the smaller of
         <ul>
-          <li>the box’s <i>available inline size</i>
-          <li>the initial containing block’s <i>inline size</i>
+          <li>the <i>available size</i>
+          <li>the initial containing block’s <i>size</i>
       </dl>
 
       <div class="note">