[css-grid-3] Remove definite-first ordering. w3c#10260 w3c#9988

Author: fantasai

css-grid-3/Overview.bs

@@ -238,14 +238,11 @@ repeat(auto-fit)</h3>
 <h3 id="masonry-layout-algorithm">
 Masonry Layout Algorithm</h3>
 
-	Items are placed in [=order-modified document order=],
-	but items with a definite placement are placed
-	before items with an indefinite position (as in regular grid layout).
+	Items are placed in [=order-modified document order=].
 
 	For each of the tracks in the [=grid axis=],
 	keep a <dfn>running position</dfn> initialized to zero.
-	First for each item with a definite placement in the [=grid axis=],
-	then for each item with an indefinite placement:
+	First for each item:
 	<ol>
 		<li>
 			If the item has an definite placement in the [=grid axis=],