Fix class name typo

Fix #13

Author: ricardoduplos

app/index.html

@@ -73,7 +73,7 @@ <h3>Adding to your project as a webfont</h3>
               </li>
               <li>
                 <p>Simply use an icon in your HTML page:</p>
-                <div class="highlight"><pre><code>&lt;span class="collecticon collecticon-house"&gt;&lt;/span&gt;</code></pre></div>
+                <div class="highlight"><pre><code>&lt;span class="collecticons collecticons-house"&gt;&lt;/span&gt;</code></pre></div>
               </li>
             </ol>
             <p>If you choose to separate the font files from the CSS files, be sure to update the links in <code>icons.css</code>.</p>
@@ -92,7 +92,7 @@ <h3>NPM</h3>
               </li>
               <li>
                 <p>Simply use an icon in your HTML page:</p>
-                <div class="highlight"><pre><code>&lt;span class="collecticon collecticon-house"&gt;&lt;/span&gt;</code></pre></div>
+                <div class="highlight"><pre><code>&lt;span class="collecticons collecticons-house"&gt;&lt;/span&gt;</code></pre></div>
               </li>
             </ol>
 
@@ -111,7 +111,7 @@ <h2 class="stripe-title">About</h2>
         </section>
       </main>
       <footer id="site-footer" role="contentinfo">
-        <p>Made with <strong class="collecticon collecticon-heart-full"><span>love</span></strong> by <a href="https://developmentseed.org" title="Visit Development Seed website">Development Seed</a>.</p>
+        <p>Made with <strong class="collecticons collecticons-heart"><span>love</span></strong> by <a href="https://developmentseed.org" title="Visit Development Seed website">Development Seed</a>.</p>
       </footer>
     </script>