[css-animations] - fix: #366 - spelling error under section 4.2 (#371)

Author: praveenpuglia

css-animations/Overview.bs

@@ -489,7 +489,7 @@ The 'animation-name' property</h3>
 		<dd>
 			The animation will use the keyframes with the name specified by the <<keyframes-name>>,
 			if they exist.
-			If no ''@keyframes'' rule with tha name exists, there is no animation.
+			If no ''@keyframes'' rule with that name exists, there is no animation.
 	</dl>
 
 <h3 id="animation-duration">