update comment

nginx/howto.ygg/betahowto.duckdns.org/server.conf

@@ -13,7 +13,7 @@ server {
     proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
     proxy_set_header X-Real-IP $remote_addr;
 
-    # Replace links
+    # Apply filters
     sub_filter_once off;
     sub_filter_types *;