[css-grid] Change the dense-packing issue to reflect thatit's now officially part of the property.

Author: tabatkins

css-grid/Overview.html

@@ -2599,12 +2599,7 @@ <h4 id=auto-placement-algo><span class=secno>6.3.1. </span> Automatic Grid
    </ol>
   </div>
 
-  <p class=issue> This algorithm creates a "sparse" packing, where holes left
-   behind are never filled in. This is more efficient and predictable (items
-   never move to a position far above/before their preceding sibling), but
-   the gaps are unwanted by authors in some situations. We should have a
-   switch to allow for dense packing. (WebKit's current implementation does
-   dense packing.)
+  <p class=issue> Edit the algorithm to allow for dense packing.
 
   <h2 id=alignment><span class=secno>7. </span> Alignment</h2>
 

css-grid/Overview.src.html

@@ -2013,15 +2013,8 @@ <h4 id='auto-placement-algo'>
 		</ol>
 	</div>
 
-
 	<p class='issue'>
-		This algorithm creates a "sparse" packing,
-		where holes left behind are never filled in.
-		This is more efficient and predictable
-		(items never move to a position far above/before their preceding sibling),
-		but the gaps are unwanted by authors in some situations.
-		We should have a switch to allow for dense packing.
-		(WebKit's current implementation does dense packing.)
+		Edit the algorithm to allow for dense packing.
 
 <h2 id='alignment'>
 Alignment</h2>