fix: correct typo for text-transform value (#2858)

math-auo -> math-auto

Author: hampusolsen

live-examples/css-examples/text/text-transform.html

@@ -42,7 +42,7 @@
   </div>
 
   <div class="example-choice">
-    <pre><code class="language-css">text-transform: math-auo;</code></pre>
+    <pre><code class="language-css">text-transform: math-auto;</code></pre>
     <button type="button" class="copy hidden" aria-hidden="true">
       <span class="visually-hidden">Copy to Clipboard</span>
     </button>