Do not suggest DEBUG logging when submitting issues

It's been pointed out that DEBUG logs could contain sensitive
information (access tokens, etc.), which makes them unsuitable
for sharing with others. INFO should be enough.

docs/maintenance-and-troubleshooting.md

@@ -21,14 +21,14 @@ sudo journalctl -fu matrix-synapse
 
 Because the [Synapse](https://github.com/matrix-org/synapse) Matrix server is originally very chatty when it comes to logging, we intentionally reduce its [logging level](https://docs.python.org/3/library/logging.html#logging-levels) from `INFO` to `WARNING`.
 
-If you'd like to debug an issue or [report a Synapse bug](https://github.com/matrix-org/synapse/issues/new/choose) to the developers, it'd be better if you temporarily increasing the logging level to `INFO` or even `DEBUG`.
+If you'd like to debug an issue or [report a Synapse bug](https://github.com/matrix-org/synapse/issues/new/choose) to the developers, it'd be better if you temporarily increasing the logging level to `INFO`.
 
 Example configuration (`inventory/host_vars/matrix.DOMAIN/vars.yml`):
 
 ```yaml
-matrix_synapse_log_level: "DEBUG"
+matrix_synapse_log_level: "INFO"
-matrix_synapse_storage_sql_log_level: "DEBUG"
+matrix_synapse_storage_sql_log_level: "INFO"
-matrix_synapse_root_log_level: "DEBUG"
+matrix_synapse_root_log_level: "INFO"
 ```
 
 Re-run the playbook after making these configuration changes.