[css-grid-1][editorial] fix linking errors

Author: tabatkins

css-grid-1/Overview.bs

@@ -42,6 +42,7 @@ WPT Path Prefix: css/css-grid/
 <pre class="link-defaults">
 spec:css-align-3;
 	type:value;
+		text:center; for:align-self;
 		text:stretch; for:align-self
 		text:stretch; for:align-content
 		text:space-between; for:justify-content
@@ -2814,7 +2815,7 @@ Numeric Indexes and Spans</h4>
 Named Lines and Spans</h4>
 
 	Instead of counting lines by number,
-	<a>named lines</a> can be referenced by their name:
+	lines can be referenced by their [=line name=]:
 
 	<div class='example'>
 		<pre>
@@ -2825,7 +2826,7 @@ Named Lines and Spans</h4>
 		</pre>
 	</div>
 
-	Note: Note that if a <a>named grid area</a> and a <a>named line</a> have the same name,
+	Note: Note that if a <a>named grid area</a> has the same name as a [=line name=],
 	the placement algorithm will prefer to use <a>named grid area</a>’s lines instead.
 
 	If there are multiple lines of the same name,
@@ -2954,7 +2955,7 @@ Line-based Placement: the 'grid-row-start', 'grid-column-start', 'grid-row-end',
 		<dt><dfn id='grid-placement-slot'><<custom-ident>></dfn>
 		<dd>
 			First attempt to match the <a>grid area</a>’s edge to a <a>named grid area</a>:
-			if there is a <a>named line</a> with the name <css><<custom-ident>>-start</css> (for 'grid-*-start') / <css><<custom-ident>>-end</css> (for 'grid-*-end'),
+			if there is a [=grid line=] whose [=line name=] is <css><<custom-ident>>-start</css> (for 'grid-*-start') / <css><<custom-ident>>-end</css> (for 'grid-*-end'),
 			contributes the first such line to the <a>grid item</a>’s <a>placement</a>.
 
 			Note: <a>Named grid areas</a> automatically generate [=implicitly-assigned line names=] of this form,