Provide syslog_format example in the man page

[myllynen]

The description for syslog_format would be clearer to with an example. Please consider adding something like below which would probably make a good default also:

syslog_format = rule,dec,perm,auid,pid,exe,:,path,ftype,trust

Thanks.

[stevegrubb]

That is the default. Anyways, commit 417d4ff solves this.