Success! Final stack:
  [(Lean.Doc.Syntax.metadata_block
    "%%%"
    (Term.structInstFields
     [(Term.structInstField
       (Term.structInstLVal `foo [])
       [[]
        []
        (Term.structInstFieldDef
         ":="
         []
         (num "53"))])
      []])
    "%%%")
   (Lean.Doc.Syntax.para
    "para{"
    [(Lean.Doc.Syntax.text
      (str "\"Text/paragraph!\""))]
    "}")]
All input consumed.