Add note re. tokens/secrets when logging to syslog.

Author: tarickb

docs/sasl-xoauth2.conf.5.md

@@ -36,7 +36,7 @@ The top-level JSON object can contain the following keys:
 
 `always_log_to_syslog`
 
-: always write plugin log messages to syslog, even for successful runs (defaults to "no")
+: always write plugin log messages to syslog, even for successful runs; may contain tokens/secrets (defaults to "no")
 
 `log_to_syslog_on_failure`