[css-grid] Rephrase collapsing issue to be a more general issue about the feature, per WG resolution.

Author: tabatkins

css-grid/Overview.html

@@ -1173,18 +1173,17 @@ <h3 id=abspos-items><span class=secno>4.2. </span> Absolutely-positioned
 
   <h3 id=visibility-collapse><span class=secno>4.3. </span> Collapsed Grid
    Items: the ‘<code class=property>visibility</code>’ property</h3>
+  <!--
+	<p>
+		Specifying ''visibility: collapse'' on a <i>grid item</i> causes it to become a <dfn title="collapsed grid item|collapsed">collapsed grid item</dfn>.
+		This has the same effect as ''visibility: hidden'',
+		except that if all the <i>grid items</i> spanning a track are <i>collapsed</i>,
+		the track's intrinsic size becomes zero.
+-->
 
-  <p> Specifying ‘<code class=css>visibility: collapse</code>’ on a <a
-   href="#grid-item"><i>grid item</i></a> causes it to become a <dfn
-   id=collapsed-grid-item title="collapsed grid item|collapsed">collapsed
-   grid item</dfn>. This has the same effect as ‘<code
-   class=css>visibility: hidden</code>’, except that if all the <a
-   href="#grid-item"><i>grid items</i></a> spanning a track are <a
-   href="#collapsed-grid-item"><i>collapsed</i></a>, the track's intrinsic
-   size becomes zero.
-
-  <p class=issue> Or should the track size be set to 0 regardless of its
-   sizing function?
+  <p class=issue> We want the ability to collapse grid tracks (similar to
+   collapsing flex items or table rows/columns), but we're not sure exactly
+   how to do it. Ideas welcome, please post them to the list.
 
   <h3 id=order-property><span class=secno>4.4. </span> Reordered Grid Items:
    the ‘<a href="#order"><code class=property>order</code></a>’ property</h3>
@@ -3754,12 +3753,6 @@ <h2 class=no-num id=index> Index</h2>
     href="#function-CalculateNormalizedFlexBreadth"
     title="section 8.2."><strong>8.2.</strong></a>
 
-   <li>collapsed, <a href="#collapsed-grid-item"
-    title="section 4.3."><strong>4.3.</strong></a>
-
-   <li>collapsed grid item, <a href="#collapsed-grid-item"
-    title="section 4.3."><strong>4.3.</strong></a>
-
    <li>column, <a href="#columns" title="section 2."><strong>2.</strong></a>
 
    <li>‘<code class=css>columns</code>’, <a href="#columns0"

css-grid/Overview.src.html

@@ -848,15 +848,16 @@ <h3 id="abspos-items">
 
 <h3 id="visibility-collapse">
 Collapsed Grid Items: the 'visibility' property</h3>
-
+<!--
 	<p>
 		Specifying ''visibility: collapse'' on a <i>grid item</i> causes it to become a <dfn title="collapsed grid item|collapsed">collapsed grid item</dfn>.
 		This has the same effect as ''visibility: hidden'',
 		except that if all the <i>grid items</i> spanning a track are <i>collapsed</i>,
 		the track's intrinsic size becomes zero.
-
+-->
 	<p class='issue'>
-		Or should the track size be set to 0 regardless of its sizing function?
+		We want the ability to collapse grid tracks (similar to collapsing flex items or table rows/columns), but we're not sure exactly how to do it.
+		Ideas welcome, please post them to the list.
 
 
 <h3 id='order-property'>