fix: dir's auto defiintion

index.html

@@ -473,7 +473,12 @@ <h3>
             "<dfn data-dfn-for="text-direction">auto</dfn>" (default)
           </dt>
           <dd>
-            No explicit directionality.
+            <p>Direction determined from content.</p>
+            <aside class="note">
+              <p>
+                An actual direction value such as `rtl` or `ltr` is preferred to relying on `auto`.
+              </p>
+            </aside>
           </dd>
         </dl>
         <p>