Fix "favicion" typo in /troubleshoot/index.html (#548)

troubleshoot/index.html

@@ -29,8 +29,8 @@
     <title>Threema Web Diagnostics</title>
 
     <!-- Favicon -->
-    <link rel="icon" href="../img/favicion/favicon.ico?v=[[VERSION]]" type="image/x-icon">
-    <link rel="shortcut icon" href="../img/favicion/favicon.ico?v=[[VERSION]]" type="image/x-icon">
+    <link rel="icon" href="../img/favicon/favicon.ico?v=[[VERSION]]" type="image/x-icon">
+    <link rel="shortcut icon" href="../img/favicon/favicon.ico?v=[[VERSION]]" type="image/x-icon">
 
     <!-- Fonts -->
     <link rel="stylesheet" href="../fonts/roboto.css?v=[[VERSION]]" type="text/css">