Fix typo (my typo)

apps/marketplace/templates/marketplace/marketplace.html

@@ -36,7 +36,7 @@
 
   <aside id="app-developer" class="span3 offset1">
     <h3>App developer?</h3>
-    <p>You can already submit your app to the Mozilla Marketplace..</p>
+    <p>You can already submit your app to the Mozilla Marketplace.</p>
     <p><a href="https://marketplace.mozilla.org/">Find out how »</a></p>
   </aside>