[css-values] Whitespace fix

Author: tabatkins

css-values/Overview.bs

@@ -878,21 +878,21 @@ Relative lengths</h3>
 	</thead>
 	<tbody>
 		<tr><td>''em''
-		    <td>font size of the element
+			<td>font size of the element
 		<tr><td>''ex''
-		    <td>x-height of the element's font
+			<td>x-height of the element's font
 		<tr><td>''ch''
-		    <td>width of the "0" (ZERO, U+0030) glyph in the element's font
+			<td>width of the "0" (ZERO, U+0030) glyph in the element's font
 		<tr><td>''rem''
-		    <td>font size of the root element
+			<td>font size of the root element
 		<tr><td>''vw''
-		    <td>1% of viewport's width
+			<td>1% of viewport's width
 		<tr><td>''vh''
-		    <td>1% of viewport's height
+			<td>1% of viewport's height
 		<tr><td>''vmin''
-		    <td>1% of viewport's smaller dimension
+			<td>1% of viewport's smaller dimension
 		<tr><td>''vmax''
-		    <td>1% of viewport's larger dimension
+			<td>1% of viewport's larger dimension
 	</tbody>
 	</table>