fix: multiple top-level headers in generic file

docs/deploying/generic.mdx

@@ -283,13 +283,13 @@ # If federation is enabled
   register but cannot join federated rooms, check your configuration and verify
   that port 8448 is open and forwarded correctly.
 
-# What's next?
+## What's next?
 
-## Audio/Video calls
+### Audio/Video calls
 
 For Audio/Video call functionality see the [Calls](../calls.md) page.
 
-## Appservices
+### Appservices
 
 If you want to set up an appservice, take a look at the [Appservice
 Guide](../appservices.md).