Parser: Display token where parser fell down

For example I misspelled device protocol
  bird: bird.conf, line 11 (nearby 'demice'): syntax error

It would be better to display whole err line. We can read it from
config->err_file_name again and display the line at config->err_lino.
32 jobs for cf-err-show-line in 6 minutes and 53 seconds (queued for 6 seconds)
latest