[css-grid-2] Remove issue; Gecko has already implemented this.

Author: fantasai

css-grid-2/Overview.bs

@@ -4304,13 +4304,6 @@ Grid Sizing Algorithm</h3>
 	including [=subgrids=] and their sub-items,
 	occurs before sizing.
 
-	Note: Track sizing in a [=subgridded=] dimension
-	treats each item in a given track in that axis
-	as members of the parent grid.
-	This interlacing requires that grid sizing
-	drill down per axis into [=subgrids=],
-	rather than completing both axes as it recurses.
-
 	<ol>
 		<li>
 			First, the <a>track sizing algorithm</a> is used to resolve the sizes of the <a>grid columns</a>.
@@ -4429,6 +4422,15 @@ Grid Sizing Algorithm</h3>
 			beyond the space allotted to during track sizing.
 	</ol>
 
+	Note: Track sizing in a [=subgridded=] dimension
+	treats each item in a given track in that axis
+	as members of the parent grid.
+	This interlacing requires that grid sizing
+	drill down per axis into [=subgrids=],
+	rather than completing both axes as it recurses.
+	Note this means that a [=subgrid=] establishing an [=orthogonal flow=]
+	would have the order of its track sizing inverted compared to a nested grid.
+
 	Once the size of each <a>grid area</a> is thus established,
 	the <a>grid items</a> are laid out into their respective containing blocks.
 	The <a>grid area’s</a> width and height are considered <a>definite</a> for this purpose.
@@ -4439,11 +4441,6 @@ Grid Sizing Algorithm</h3>
 	the size of a grid item which is stretched
 	is also considered definite.
 
-	Issue: Note, this means that a subgrid establishing an orthogonal flow
-	would have the order of its track sizing inverted compared to a nested grid.
-	We could simplify this by saying that an orthogonal flow
-	cannot establish a subgrid; it can only be a nested grid.
-
 	<div class="example">
 		The following example illustrates how per-axis subgrids are sized: