Add clarification about whitelabeling headers.

Author: tasn

docs/receiving/verifying-payloads/how-manual.mdx

@@ -20,7 +20,7 @@ Each webhook call includes three headers with additional information that are us
 * `svix-signature`: the [Base64](https://en.wikipedia.org/wiki/Base64) encoded list of signatures (space delimited).
 
 :::info
-Professional tier customers can have the headers white-labeled to use the `webhook-` prefix instead of the `svix-` prefix used above. The Svix libraries support both.
+Professional and Enterprise tier customers can have the headers white-labeled to use the `webhook-` prefix instead of the `svix-` prefix used above. The Svix libraries support both.
 :::
 
 ### Constructing the signed content