[css-flexbox] typo

Author: tabatkins

css-flexbox/Overview.bs

@@ -2181,7 +2181,7 @@ Flex Container Baselines</h3>
 				and its first/last <a>flex item</a> has a baseline
 				parallel to the flex container's <a>main axis</a>,
 				the flex container's first/last <a>main-axis baseline set</a>
-				is a lt="generate baselines">generated</a> from
+				is <a lt="generate baselines">generated</a> from
 				its <a>alignment baseline</a>.
 
 			3. Otherwise, the flex container's first/last <a>main-axis baseline set</a>