Who says "Goodnight nobody?"

But what's the meaning behind "goodnight noises everywhere"?

I’ve wondered that for a while, especially combined with the previous pages saying “goodnight stars, goodnight air”

I love that part, and also "goodnight nobody" - the book starts out being very concrete (saying good night to all the things in the room) then expands out to encompass everything and nothing. It feels at once poetic and childlike.