Fixes https://github.com/PurpleI2P/i2pd/issues/1540

docs/user-guide/configuration.md

@@ -19,7 +19,7 @@ For example:
 i2pd.conf:
 
     # comment
-    log = true
+    log = true # use stdout (default)
     ipv6 = true
     # settings for specific module
     [httpproxy]
@@ -47,7 +47,7 @@ Option                                 | Description
 conf                                   | Config file (default: ~/.i2pd/i2pd.conf or /var/lib/i2pd/i2pd.conf). This parameter will be silently ignored if the specified config file does not exist.
 tunconf                                | Tunnels config file (default: ~/.i2pd/tunnels.conf or /var/lib/i2pd/tunnels.conf)
 pidfile                                | Where to write pidfile (default: i2pd.pid, not used in Windows)
-log                                    | Logs destination: stdout, file, syslog (stdout if not set, file - otherwise, for compatibility)
+log                                    | Logs destination: stdout, file, syslog (stdout if not set or invalid) (if daemon, stdout/unspecified are replaced by file in some cases)
 logfile                                | Path to logfile (default - autodetect)
 loglevel                               | Log messages above this level (debug, info, warn, error, none; default - info)
 logclftime                             | Write full CLF-formatted date and time to log (default: write only time)