Updated "server.error-handler-404" override
Updated "server.error-handler-404" override

Tested, this time. It appears to work correctly with a [default Pi-hole config](https://github.com/pi-hole/pi-hole/blob/master/advanced/lighttpd.conf.debian), and shouldn't get overwritten by a PH update (unlike directly modifying "server.error-handler-404", which is the proper way to handle this!)
WaLLy3K/Pi-hole-Block-Page