Insert a newline manually in Jade

I have a mixin looking like this

mixin preprocessor_instructions()
  some text goes here

This is not actualy just text, but more some tech instruction for my preprocessor. I don't want it to be inside any tag. The problem is when I use this mixin in Jade template like this

+preprocessor_instructions

it doesn't insert a newline in the output html before this piece of code though I would like to see it there to have it look pretty. How can I insert a newline manually using Jade?

You can use inline HTML:

mixin preprocessor_instructions()
  | //- <- note the space after the pipe
  some text goes here

+preprocessor_instructions