Update simple-selectors-after.html

Closed the span tag. See: https://www.coursera.org/learn/html-css-javascript-for-web-developers/lecture/jI4A3/lecture-13-element-class-and-id-selectors/discussions/vlr7e-nuEeW3AhKGdOu9ew?utm_medium=email&utm_source=other&utm_campaign=opencourse.discourse.html-css-javascript-for-web-developers~opencourse.discourse.vhLVVTe9EeWnxw5wP_KHTw.vlr7e-nuEeW3AhKGdOu9ew

Author: JSONRice

examples/Lecture13/simple-selectors-after.html

@@ -46,7 +46,7 @@ <h2>Subheading 1 (h2)</h2>
 <h2>Subheading 2 (h2)</h2>
 <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Eligendi nemo ipsum dolores vel modi magnam veniam alias at nam. Voluptatem officiis dolor dolorem aspernatur dolorum modi ipsa, nobis animi aut!</p>
 <div>This is the main point of the entire article. So, attribute 
-<span id="mainPoint">id="mainPoint".</span </div>
+<span id="mainPoint">id="mainPoint".</span> </div>
 
 </body>
 </html>