Success! Final stack:
  [(Lean.Doc.Syntax.para
    "para{"
    [(Lean.Doc.Syntax.text
      (str "\"Newlines are preserved\""))
     (Lean.Doc.Syntax.linebreak
      "line!"
      (str "\"\\n\""))
     (Lean.Doc.Syntax.text
      (str "\"in paragraphs.\""))]
    "}")]
All input consumed.