add missing hrefs to <a>s in docs+examples

docs/_includes/components/jumbotron.html

@@ -6,14 +6,14 @@
     <div class="jumbotron">
       <h1>Hello, world!</h1>
       <p>This is a simple hero unit, a simple jumbotron-style component for calling extra attention to featured content or information.</p>
-      <p><a class="btn btn-primary btn-lg" role="button">Learn more</a></p>
+      <p><a class="btn btn-primary btn-lg" href="#" role="button">Learn more</a></p>
     </div>
   </div>
 {% highlight html %}
 <div class="jumbotron">
   <h1>Hello, world!</h1>
   <p>...</p>
-  <p><a class="btn btn-primary btn-lg" role="button">Learn more</a></p>
+  <p><a class="btn btn-primary btn-lg" href="#" role="button">Learn more</a></p>
 </div>
 {% endhighlight %}
   <p>To make the jumbotron full width, and without rounded corners, place it outside all <code>.container</code>s and instead add a <code>.container</code> within.</p>

docs/examples/jumbotron/index.html

@@ -59,7 +59,7 @@
       <div class="container">
         <h1>Hello, world!</h1>
         <p>This is a template for a simple marketing or informational website. It includes a large callout called a jumbotron and three supporting pieces of content. Use it as a starting point to create something more unique.</p>
-        <p><a class="btn btn-primary btn-lg" role="button">Learn more &raquo;</a></p>
+        <p><a class="btn btn-primary btn-lg" href="#" role="button">Learn more &raquo;</a></p>
       </div>
     </div>