Mastodon nginx: tweak backend locations

installation/mastodon.conf

@@ -67,7 +67,7 @@ server {
 
   # Mastodon backend routes.
   # These are routes to Mastodon's API and important rendered pages.
-  location ~ ^/(api|oauth|auth|admin|.well-known/webfinger) {
+  location ~ ^/(api|oauth|auth|admin|manifest.json|.well-known/webfinger|@(.+)/embed$) {
     try_files /dev/null @proxy;
   }