Merge pull request #2768 from luotao1/fork

mistaken: Folk -> Fork in develop branch

doc_theme/templates/layout.html

@@ -101,7 +101,7 @@
     </div>
     <div class="site-nav-links">
       <div class="site-menu">
-        <a class="fork-on-github" href="https://github.com/PaddlePaddle/Paddle" target="_blank"><i class="fa fa-github"></i>Folk me on Github</a>
+        <a class="fork-on-github" href="https://github.com/PaddlePaddle/Paddle" target="_blank"><i class="fa fa-github"></i>Fork me on Github</a>
         <div class="language-switcher dropdown">
           <a type="button" data-toggle="dropdown">
             <span>English</span>