Update head-custom.html

Author: tballmsft

_includes/head-custom.html

@@ -1,4 +1,4 @@
-<meta http-equiv="Refresh" content="0; url='https://microbit-apps.github.io/microcode-classic'" />
+<meta http-equiv="Refresh" content="0; url='https://microbit-apps.github.io/microcode-classic/docs/manual'" />
 <link rel="apple-touch-icon" href="/{{ site.github.repository_name }}/assets/image.png" />
 <link rel="icon" type="image/png" href="/{{ site.github.repository_name }}/assets/image.png" />
 <script type="text/javascript">
@@ -16,4 +16,4 @@
         isCookieUseDisabled: true,
         isStorageUseDisabled: true
     }});
-</script>
+</script>