Add missing title to "about" section

lib/templates/cv.html.heex

@@ -54,7 +54,8 @@
       <Basics.basics name={@basics.name} title={@basics.label} />
     </div>
 
-    <div id="about">
+    <div id="about" class="section">
+      <h1>tl;dr</h1>
       <Basics.about summary={@basics.summary} />
     </div>