[css-grid] Add implict named lines to changes sectin.

Author: tabatkins

css-grid/Overview.html

@@ -4425,4 +4425,7 @@ <h2 class=no-num id=changes> Changes</h2>
     value from ‘<a href="#grid-auto-flow"><code
     class=property>grid-auto-flow</code></a>’, turning auto-placement on by
     default so that grid items by default don't stack on top of each other.
+
+   <li>Made named grid areas <a href="#implict-named-lines">imply named grid
+    lines</a>.
   </ul>

css-grid/Overview.src.html

@@ -2919,4 +2919,5 @@ <h2 class="no-num" id="changes">
 		<li>Marked <a href="#visibility-collapse">grid row/column collapsing</a> as an open issue.
 		<li>Changed the syntax of <a href="#named-lines">named lines</a> to use parentheses and identifiers rather than strings.
 		<li>Removed the ''none'' value from 'grid-auto-flow', turning auto-placement on by default so that grid items by default don't stack on top of each other.
+		<li>Made named grid areas <a href="#implict-named-lines">imply named grid lines</a>.
 	</ul>