config files: Nimscript and Nim compiler documentation inconsistency

[cblake]

@slonik_az \- I see. I did not see the definition of project as just the .nim 
file and interpreted "project" more as the wider world does more often as some 
kind of filesystem directory/folder. Good catch and sorry for the noise. As 
said, I suspect ignoring the old style `.cfg` is the right choice.