change EROR to ERROR in the logs

[art0007i]

I assume it's EROR so that it lines up nicely with other messages, but I think it would actually be better for errors stand out a bit since they are usually meant for when something breaks, and it means the word is actually spelled correctly too

[XDelta]

All the log levels are set as 4 character variants as part of serilogs formatting string. I don't currently intend on changing that.