add trailing slash if /convert/ is loaded without its trailing slash

docs/example.nginx.conf

@@ -237,7 +237,7 @@ server {
     # The nodejs server has some built-in forwarding rules to prevent
     # URLs like /pad from resulting in a 404. This simply adds a trailing slash
     # to a variety of applications.
-    location ~ ^/(register|login|settings|user|pad|drive|poll|slide|code|whiteboard|file|media|profile|contacts|todo|filepicker|debug|kanban|sheet|support|admin|notifications|teams|calendar|presentation|doc|form|report|convert)$ {
+    location ~ ^/(register|login|settings|user|pad|drive|poll|slide|code|whiteboard|file|media|profile|contacts|todo|filepicker|debug|kanban|sheet|support|admin|notifications|teams|calendar|presentation|doc|form|report|convert|checkup)$ {
         rewrite ^(.*)$ $1/ redirect;
     }