add favicon (#457)

Author: Arhell

_layouts/bootstrap.html

@@ -12,7 +12,7 @@
     <meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
 
     <!-- CSS -->
-  <link href="https://fonts.googleapis.com/css2?family=Roboto+Mono:wght@400;500;700&display=swap" rel="stylesheet">
+    <link href="https://fonts.googleapis.com/css2?family=Roboto+Mono:wght@400;500;700&display=swap" rel="stylesheet">
     <link href="https://fonts.googleapis.com/css?family=Lato&display=swap" rel="stylesheet">
     <link href="//netdna.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css" rel="stylesheet">
 
@@ -23,6 +23,7 @@
     <link rel="apple-touch-icon" sizes="180x180" href="/apple-touch-icon.png">
     <link rel="icon" type="image/png" sizes="32x32" href="/favicons/favicon-32x32.png">
     <link rel="icon" type="image/png" sizes="16x16" href="/favicons/favicon-16x16.png">
+    <link rel="icon" type="image/png" sizes="16x16" href="/favicon.ico">
     <link rel="manifest" href="/favicons/site.webmanifest">
     <link rel="mask-icon" href="/favicons/safari-pinned-tab.svg" color="#236BFD">
     <meta name="msapplication-config" content="/favicons/browserconfig.xml" />