updated whatsapp config

docs/configuring-playbook-bridge-mautrix-whatsapp.md

@@ -13,11 +13,18 @@ matrix_mautrix_whatsapp_enabled: true
 ## Enable backfilling history
 This requires a server with MSC2716 support, which is currently an experimental feature in synapse.
 Note that as of Synapse 1.46, there are still some bugs with the implementation, especially if using event persistence workers.
-
 Use the following playbook configuration:
 
 ```yaml
-matrix_bridges_backfill_enabled: true
+matrix_synapse_configuration_extension_yaml: |
+  experimental_features:
+    msc2716_enabled: true
+```
+```yaml
+matrix_mautrix_whatsapp_configuration_extension_yaml:
+  bridge:
+    history_sync:
+      backfill: true
 ```
 
 ## Set up Double Puppeting