update link

components/button.md

@@ -1,7 +1,7 @@
 # Button 按钮
 
 - category: Component
-- API: github.com/react-component/dialog
+- API: github.com/react-component/button
 
 ---
 

components/select.md

@@ -1,6 +1,7 @@
 # Select 选择框
 
 - category: Component
+- API: github.com/react-component/select
 
 ---
 

theme/templates/layout.html

@@ -74,10 +74,12 @@
     <article class="markdown">
       <h1>
         {{ post.title }}
+        {%- if post.meta.API %}
         <a class="api-link" href="http://{{ post.meta.API }}" target="_blank">
           <i class="iconfont icon-externallink"></i>
           API 使用说明
         </a>
+        {%- endif %}
       </h1>
       {{ post.html }}
     </article>