Add favicon

assets/page.html

@@ -4,6 +4,7 @@
         <meta charset="UTF-8" />
         <meta name="viewport" content="width=device-width, initial-scale=1" />
         <title>{{.Title}}</title>
+        <link rel="icon" href="/_/favicon.ico" />
         <link rel="stylesheet" href="/_/style.css" />
         <script src="/_/global-shortcuts.js"></script>
     </head>