Update docs/configuring-playbook-bridge-hookshot.md: add the common section "Troubleshooting"

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

docs/configuring-playbook-bridge-hookshot.md

@@ -143,3 +143,16 @@ Whichever one you go with, by default metrics are exposed publicly **without** p
 ### Collision with matrix-appservice-webhooks
 
 If you are also running [matrix-appservice-webhooks](configuring-playbook-bridge-appservice-webhooks.md), it reserves its namespace by the default setting `matrix_appservice_webhooks_user_prefix: '_webhook_'`. You should take care if you modify its or hookshot's prefix that they do not collide with each other's namespace (default `matrix_hookshot_generic_userIdPrefix: '_webhooks_'`).
+
+## Troubleshooting
+
+As with all other services, you can find the logs in [systemd-journald](https://www.freedesktop.org/software/systemd/man/systemd-journald.service.html) by logging in to the server with SSH and running `journalctl -fu matrix-bridge-hookshot`.
+
+### Increase logging verbosity
+
+The default logging level for this component is `warn`. If you want to increase the verbosity, add the following configuration to your `vars.yml` file and re-run the playbook:
+
+```yaml
+# Valid values: debug, info, warn, error
+matrix_hookshot_logging_level: debug
+```