[css-overflow-4] Tweaks example

Author: frivoal

css-overflow-4/Overview.bs

@@ -682,7 +682,7 @@ ellipsis interaction with scrolling interfaces</h3>
 <div class="example">
 Same as previous example except with <code>text-overflow: ellipsis ellipsis</code>, demonstrated:
 
-<div style="text-overflow: ellipsis ellipsis; height: 2em; overflow: scroll; white-space: nowrap; width: 15em; border:1em solid black;">
+<div style="text-overflow: ellipsis ellipsis; height: 2em; line-height: 1em; overflow: scroll; white-space: nowrap; width: 15em; border:1em solid black;">
 CSS is awesome, especially when you can scroll
 to see extra text instead of just
 having it overlap other text by default.