Add warning header to server config file

[TelepathicGrunt]

maybe in 1.22 we can rename the config names. But for now, we could add a header to the server config file that warns people that the file is synced to client and to not add sensitive info. Which then will cause users to tell modders to fix their mods if a modder has a token field or something in server configs

[shartte]

@TelepathicGrunt Did Nightconfig actually move on this? I don't remember but I do remember you pinged will over it.

[TelepathicGrunt]

https://github.com/TheElectronWill/night-config/issues/193