Fixing remove runtime

src/teaching/cse-250/2022fa/slide/9b-LinkedListIterator.erb

@@ -251,7 +251,13 @@ textbook: "Ch. 7"
 </section>
 
 <section>
-  <p>An iterator is a reference to an element of the collection</p>
+  <p>An iterator is:
+    <ul>
+      <li>A reference to an element of the collection</li>
+      <li>A way to get to the next<sup class="fragment" data-fragment-index=1>1</sup> element of the collection.</li>
+    </ul> 
+  </p>
+  <p class="fragment" data-fragment-index=1>1: For some definition of next.</p>
 </section>
 
 <section>