feat: 增加mermaid支持

docs/index.html

@@ -117,6 +117,9 @@
   
   <!-- <link rel="stylesheet" href="//unpkg.com/mermaid/dist/mermaid.min.css"> -->
   <!-- <script src="//unpkg.com/mermaid/dist/mermaid.min.js"></script> -->
+  
+  <link rel="stylesheet" href="//unpkg.com/mermaid/dist/mermaid.min.css">
+  <script src="//unpkg.com/mermaid/dist/mermaid.min.js"></script>
   <!-- 公式 -->
   <!-- CDN files for docsify-katex -->
   <script src="./static/js/katex.min.js" ></script>