docs: add comment to security headers

docker/nginx.conf

@@ -10,6 +10,7 @@ server {
 
     gzip_static on;
 
+    # Deny IE browsers from going into quirks mode
     add_header X-UA-Compatible "IE=Edge";
     # X-Frame-Options is to prevent from clickJacking attack
     add_header X-Frame-Options SAMEORIGIN;