Docblock comment refmts with parens around documented item:

  /** raise the same error than if we failed to match */
  (
    if (! Re_pcre.pmatch(~rex=allR, err)) {
      raise(Not_found);
    } else {
      let hintR = {|Syntax error:([\s\S]+)|};
      let hint = get_match_maybe(hintR, err);
      /* assuming on the same row */
      let ((startRow, startColumn), (_, endColumn)) = range;
      File_SyntaxError({
        hint: Helpers.optionMap(String.trim, hint),
        offendingString:
          Helpers.stringSlice(
            ~first=startColumn,
            ~last=endColumn,
            List.nth(cachedContent, startRow),
          ),
      });
    }
  );

The /** comment is actually a ppx attribute in the shape/style of a comment so they must be syntactically valid - however, I don't think the parens are required here at print time because it parses fine.

Start with the refmt formatting path for Reason docblock attributes and reproduce the issue using the snippet in this report. Compare the printed output with the accepted syntax, and consider the work complete when valid parenthesized expressions no longer retain unnecessary parentheses after formatting.