[css-inline] fix duplicate ID

Author: dauwhe

css-inline/Overview.bs

@@ -840,7 +840,7 @@ href="/TR/REC-CSS2/media.html#visual-media-group">visual</a>
 <td>see individual properties</table>
 
 
-<h2 id="baseline">Baseline alignment</h2>
+<h2 id="baseline-alignment">Baseline alignment</h2>
 
 <p>Baseline alignment describes the alignment of textual content and based on
 information contained in&nbsp; font tables associated with font resources.