docs: function setOpening(tokenOrLexer) {
      metaObj.line = tokenOrLexer.line;
      metaObj.col = tokenOrLexer.col;
  
      // whitespace or comments that preceded the opening token
      // (e.g. on a () list whitespace or comments that preceded "(")
      metaObj.prelude = tokenOrLexer.prelude;
    }