Improved German doctrine structure with semantic HTML updates and added lang attributes for enhanced accessibility.

Author: liberaldev

doctrine/de.html

@@ -33,22 +33,22 @@ <h1>Die Rails-Doktrin.</h1>
           </label>
           <div class="language__options">
             <ul>
-              <li>
+              <li lang="en">
                 <a href="/doctrine/"><span>English</span></a>
               </li>
-              <li>
+              <li lang="es">
                 <a href="/doctrine/es"><span>Español</span></a>
               </li>
-              <li>
+              <li lang="es">
                 <a href="/doctrine/fr"><span>Français</span></a>
               </li>
-              <li>
+              <li lang="en">
                 <a href="/doctrine/ru"><span>Russian</span></a>
               </li>
-              <li>
+              <li lang="zh-CN">
                 <a href="/doctrine/zh_cn"><span>简体中文</span></a>
               </li>
-              <li>
+              <li lang="zh-TW">
                 <a href="/doctrine/zh_tw"><span>繁體中文</span></a>
               </li>
             </ul>