Indentation of infix extension in `try` blocks

[atemp]

If an infix extension is added to a try, the expression is indented by 6 spaces instead of 2:

let _ =
  try%lwt
        1
  with
    _ -> 2

A try without an extension works:

let _ =
  try
    1
  with
    _ -> 2

IMHO the try%lwt should be indented like that:

let _ =
  try%lwt
    1
  with
    _ -> 2

• try is defined here: https://ocaml.org/releases/4.11/htmlman/expr.html
• infix extensions are defined here: https://ocaml.org/releases/4.11/htmlman/extensionnodes.html