Update docs/configuring-playbook-element-call.md

Co-authored-by: Suguru Hirahara <luixxiul@users.noreply.github.com>

docs/configuring-playbook-element-call.md

@@ -36,6 +36,7 @@ keydb_enabled: true
 matrix_element_call_enabled: true
 matrix_livekit_server_enabled: true
 matrix_jwt_service_enabled: true
+
 # Set a secure key for LiveKit authentication
 matrix_livekit_server_dev_key: 'your-secure-livekit-key'
 ```