[css-display-1] Fix references.

Author: fantasai

css-display-3/Overview.bs

@@ -501,7 +501,7 @@ Inner Display Layout Models: the ''flow'', ''flow-root'', ''table'', ''flex'', '
 		<dt><dfn>flex</dfn>
 		<dd>
 			The element generates a principal <a>flex container</a> box
-			and establishes a <a>flex formatting context</a>. [[!CSS3-FLEXBOX]]
+			and establishes a <a>flex formatting context</a>. [[!CSS-FLEXBOX-1]]
 
 		<dt><dfn>grid</dfn>
 		<dd>
@@ -1783,7 +1783,9 @@ Changes</h2>
 
 	<ul>
 		<li id="change-move-order">
-			Took the 'order' property from [[css-flexbox-1]].
+			Pulled in the 'order' property definition from [[CSS-FLEXBOX-1]],
+			since it also applies to [=grid items=].
+			(<a href="https://github.com/w3c/csswg-drafts/issues/5865">Issue 5865</a>)
 		<li id="change-internal-replaced">
 			Defined that [=replaced elements=] with a [=layout-internal=] 'display'
 			are treated as ''display: inline''.