[css-egg] markup typo

Author: tabatkins

css-egg/Overview.bs

@@ -341,7 +341,7 @@ This specification extends the 'voice-rate' property, so that the ''tmbl'' unit
 
 <pre class="propdef partial" noexport>
     Name: voice-rate
-    New Values: [normal | x-slow | slow | medium | fast | x-fast | <<speech-rate>>] || &lt;percentage&gt;
+    New values: [normal | x-slow | slow | medium | fast | x-fast | <<speech-rate>>] || &lt;percentage&gt;
 </pre>
 
 Issue: Should negative values be allowed for <<speech-rate>> for reversed speech?