added docsify-copy-code plugin

index.html

@@ -35,6 +35,7 @@
     Recommended
     <script src="https://cdn.jsdelivr.net/npm/docsify@4/lib/plugins/search.js"></script>
     <script src="https://cdn.jsdelivr.net/npm/docsify-tabs@1"></script>
+    <script src="//cdn.jsdelivr.net/npm/docsify-copy-code"></script>
 </body>
 
 </html>