[css-grid] Resolve abspos 'auto' offsets to padding edge of grid container, per WG resolution.

Author: tabatkins

css-grid/Overview.html

@@ -1164,20 +1164,8 @@ <h3 id=abspos-items><span class=secno>4.2. </span> Absolutely-positioned
    href="#grid-item"><i>grid items</i></a>. In this case, an ‘<a
    href="#track-size-auto"><code class=css>auto</code></a>’ value for a <a
    href="#grid-placement-properties"><i>grid-placement property</i></a>
-   indicates ...
-
-  <div class=issue>
-   <ul>
-    <li>the padding edge of the <a href="#grid-container"><i>grid
-     container</i></a> (as normal for abspos)
-
-    <li>the "default cell" of the grid, whenever we define that
-
-    <li>the next/previous grid line (as normal for grid items with one ‘<a
-     href="#track-size-auto"><code class=css>auto</code></a>’ value in a
-     dimension, as it resolves to ‘<code class=css>span 1</code>’)
-   </ul>
-  </div>
+   indicates the corresponding padding edge of the <a
+   href="#grid-container"><i>grid container</i></a>.
 
   <p class=note> This can allow an abspos to "skip past" intervening grid
    containers, and resolve its grid-placement properties against a grid

css-grid/Overview.src.html

@@ -839,15 +839,7 @@ <h3 id="abspos-items">
 		is generated by a <i>grid container</i>,
 		the <i>grid-placement properties</i> can be used to constrain it to a particular <i>grid area</i>,
 		similar to how they affect regular <i>grid items</i>.
-		In this case, an ''auto'' value for a <i>grid-placement property</i> indicates ...
-
-	<div class="issue">
-		<ul>
-			<li>the padding edge of the <i>grid container</i> (as normal for abspos)
-			<li>the "default cell" of the grid, whenever we define that
-			<li>the next/previous grid line (as normal for grid items with one ''auto'' value in a dimension, as it resolves to 'span 1')
-		</ul>
-	</div>
+		In this case, an ''auto'' value for a <i>grid-placement property</i> indicates the corresponding padding edge of the <i>grid container</i>.
 
 	<p class='note'>
 		This can allow an abspos to "skip past" intervening grid containers,