add a sample logging.conf in docs/misc (#4380)

add a sample logging.conf in docs/misc

(and point to it in the man page)

docs/misc/logging.conf

@@ -0,0 +1,23 @@
+[loggers]
+keys=root
+
+[handlers]
+keys=logfile
+
+[formatters]
+keys=logfile
+
+[logger_root]
+level=NOTSET
+handlers=logfile
+
+[handler_logfile]
+class=FileHandler
+level=INFO
+formatter=logfile
+args=('borg.log', 'w')
+
+[formatter_logfile]
+format=%(asctime)s %(levelname)s %(message)s
+datefmt=
+class=logging.Formatter

docs/usage_general.rst.inc

@@ -202,6 +202,7 @@ General:
         use fqdn@uniqueid.
     BORG_LOGGING_CONF
         When set, use the given filename as INI_-style logging configuration.
+        A basic example conf can be found at ``docs/misc/logging.conf``.
     BORG_RSH
         When set, use this command instead of ``ssh``. This can be used to specify ssh options, such as
         a custom identity file ``ssh -i /path/to/private/key``. See ``man ssh`` for other options. Using