title: Icon accessibility within links (aria-hidden)
body: <p>Suppose I have two arrows on either end of a carousel which when clicked rotate the carousel.  I might have markup like:</p>
  
  <pre><code>&lt;a class="carousel-prev" alt="Previous Item"&gt;&lt;i class="icon-angle-left" aria-hidden="true"&gt;&lt;/i&gt;&lt;/a&gt;
  &lt;a class="carousel-next" alt="Next Item"&gt;&lt;i class="icon-angle-right" aria-hidden="true"&gt;&lt;/i&gt;&lt;/a&gt;
  </code></pre>
  
  <p>In this case, does <code>aria-hidden="true"</code> attribute break accessibility, or is it okay since the outer <code>&lt;a&gt;</code> tag is tabbable and is using alt text?</p>