Describe the bug
The newline escapes in this string literal are past the 90-character margin:

let _ =
  "_ _____________________ ___________ ________ _____________ ________ _____________ _____\n\n\
  \ ___________________ ______ _____ ___________ _______ _____ _____ __ ___ ______ ___"
;;

How to Reproduce
Style the above file with ocamlformat --profile=janestreet, using ocamlformat built from f6bc80a (the gpetiot/janestreet branch).