Bug: Empty comment block recognized as documentation comment

[crackcomm]

Describe the bug

Empty comment block (**) is recognized as documentation comment and triggers a warning:

58 |   (**)
       ^^^^
Warning 50 [unexpected-docstring]: unattached documentation comment (ignored)
Hint: (Warning 50) This file contains a documentation comment (** ... *) that the OCaml compiler does not know how to attach to the AST. OCamlformat does not support these cases. You can find more information at: https://github.com/ocaml-ppx/ocamlformat#overview. If you'd like to disable this check and let ocamlformat make a choice (though it might not be consistent with the ocaml compilers and odoc), you can set the --no-comment-check option.

[Julow]

I guess the source looks like this: (the comment is in an expression)

let _ =
  (**)
  ()

Unfortunately, there's nothing we can do as the warning is real. The compiler do not report it by default as comments have no impact on the type checking but it can be seem with ocamlc -w +50.

OCamlformat cares about this warning as this comment is very hard to print again in the right location.