a11y - 2.2.2 changing a DIV to an H3 (es was ok)

cur/programming/2-complexity/2-data-structures-art/2-quizzes.html

@@ -104,7 +104,7 @@ <h2>Planning a Quiz App</h2>
                     <div class="ap-standard">AAP-1.D</div>
                     Build the custom <code>quiz item</code> abstract data type (both the constructor and the two selectors).
                     <div class="narrower">
-                        <div class="box-head">Specifying an Input Type</div>
+                        <h3 class="box-head">Specifying an Input Type</h3>
                         <p>Your selectors expect a quiz item, i.e., a list, as input.  You can make your blocks <em>show</em> what type of data they expect. It's not necessary in Snap<em>!</em> but, like assigning a color to a block, it can be a helpful reminder of what the block does and what type of input it expects. You've already seen input slots of several shapes, indicating different expected data types. </p>
                         <p>
                             In the Block Editor while creating a selector, click on a plus sign to enter an input name.  Then...