Failure @45 (⟨2, 29⟩): expected link target '(url)' or '[ref]' (use '\[' for a literal '[')
Final stack:
  [(Lean.Doc.Syntax.para
    "para{"
    [(Lean.Doc.Syntax.link
      "["
      [(Lean.Doc.Syntax.text (str "\"My link\""))]
      "]"
      (Lean.Doc.Syntax.ref
       "["
       (str "\"lean\"")
       "]"))
     (Lean.Doc.Syntax.linebreak
      "line!"
      (str "\"\\n\""))
     (Lean.Doc.Syntax.link
      "["
      [(Lean.Doc.Syntax.text (str "\"lean\""))]
      "]"
      (Lean.Doc.Syntax.url <missing>))]
    "}")]
Remaining: ""