Fix documentation on system hardening.

[erikdemarco]

I have issue with this error:

  failed to start (exit status -1) – Program /some/path/script.sh failed: File '/some/path/script.sh' does not exist
  failed to start (exit status -1) – no output

But the FAQ doesnt tell how to fix this issue (which setting should be disabled), only tell "this is the cause" without telling which specific core setting to disable and how without considering not all monit users advanced users:
https://mmonit.com/wiki/Monit/FAQ#hardening