[css-align] Add grid containers to the table for the *-content stuff.

Author: tabatkins

css-align/Overview.bs

@@ -117,11 +117,11 @@ Overview of Alignment Properties</h2>
 				<img src="images/content-example.svg" width=106 height=106 alt="">
 				content within element
 				<small>(effectively adjusts padding)</small>
-			<td>block containers and flex containers
+			<td>block containers, <a>flex containers</a>, and <a>grid containers</a>
 		<tr>
 			<th>'align-content'
 			<td>stacking
-			<td>block containers and flex containers
+			<td>block containers, <a>flex containers</a>, and <a>grid containers</a>
 	<tbody>
 		<tr>
 			<th>'justify-self'
@@ -130,11 +130,11 @@ Overview of Alignment Properties</h2>
 				<img src="images/self-example.svg" width=106 height=106 alt="">
 				element within parent
 				<small>(effectively adjusts margins)</small>
-			<td>block-level elements and grid items
+			<td>block-level elements and <a>grid items</a>
 		<tr>
 			<th>'align-self'
 			<td>stacking
-			<td>flex items and grid items
+			<td><a>flex items</a> and <a>grid items</a>
 	<tbody>
 		<tr>
 			<th>'justify-items'
@@ -143,11 +143,11 @@ Overview of Alignment Properties</h2>
 				<img src="images/items-example.svg" width=106 height=106 alt="">
 				items inside element
 				<small>(controls child items&rsquo; ''align/justify-self: auto'')</small>
-			<td>grid containers
+			<td><a>grid containers</a>
 		<tr>
 			<th>'align-items'
 			<td>stacking
-			<td>flex containers and grid containers
+			<td><a>flex containers</a> and <a>grid containers</a>
 	</table>
 
 	<p class=issue>