Success! Final stack:
  [(Lean.Doc.Syntax.blockquote
    ">"
    [(Lean.Doc.Syntax.para
      "para{"
      [(Lean.Doc.Syntax.text (str "\"hey\""))
       (Lean.Doc.Syntax.linebreak
        "line!"
        (str "\"\\n\""))]
      "}")])]
All input consumed.