update example nginx config for spreadsheets

docs/example.nginx.conf

@@ -46,6 +46,8 @@ server {
 
     set $unsafe 0;
     if ($uri = "/pad/inner.html") { set $unsafe 1; }
+    if ($uri = "/sheet/inner.html") { set $unsafe 1; }
+    if ($uri = "/common/onlyoffice/web-apps/apps/spreadsheeteditor/main/index.html") { set $unsafe 1; }
     if ($host != sandbox.cryptpad.info) { set $unsafe 0; }
     if ($unsafe) {
         set $scriptSrc "'self' 'unsafe-eval' 'unsafe-inline' new2.cryptpad.fr cryptpad.fr";
@@ -95,7 +97,7 @@ server {
         try_files $uri =404;
     }
 
-    location ~ ^/(register|login|settings|user|pad|drive|poll|slide|code|whiteboard|file|media|profile|contacts|todo|filepicker|debug|kanban)$ {
+    location ~ ^/(register|login|settings|user|pad|drive|poll|slide|code|whiteboard|file|media|profile|contacts|todo|filepicker|debug|kanban|sheet)$ {
         rewrite ^(.*)$ $1/ redirect;
     }