Some remarks to stdlib documentation

[StefanSalewski]

Miran, I think for https://nim-lang.github.io/Nim/io.html#lines.i%2CFile there should be a note on the top that io is part of system so that we do not have to import module io. (I just tried to import it :-( )

And for https://nim-lang.github.io/Nim/algorithm.html are you sure that at top

proc myCmp(x, y: People): int =
  if x.name < y.name: -1 else: 1

is really fully correct? Should it not return zero for equality?