[css-ui-4] Fix typo

Author: frivoal

css-ui-4/Overview.bs

@@ -2513,7 +2513,7 @@ Switching form control sizing: the 'field-sizing' property</h3>
 	</dl>
 
 	<div class="example">
-		For instance, <{textara}> has fixed size regardless of its content by default:
+		For instance, <{textarea}> has fixed size regardless of its content by default:
 
 		<span class="fake-textarea auto">&#x23B8;</span>
 		<span class="fake-textarea auto">The quick brown fox jumps over the lazy dog.</span>