Add note on delay before becoming accessible

Author: bbiggerr

openapi.yaml

@@ -3583,7 +3583,7 @@ paths:
       description: |
         Creates a snapshot backup of a Managed MySQL Database.
 
-        Backups generated by this command have the type `snapshot`.
+        Backups generated by this command have the type `snapshot`. Snapshot backups may take several minutes to complete, after which they will be accessible to view or restore.
 
         The Database must have an `active` status to perform this command.