Update documentation (#337)

documentation updated, from the comments - #309 (comment)

readme.md

@@ -68,7 +68,7 @@ To disable the first type, you could mock the console.log and console.warn APIs,
 
     pdfParser.on("pdfParser_dataError", errData => console.error(errData.parserError) );
     pdfParser.on("pdfParser_dataReady", pdfData => {
-        fs.writeFile("./pdf2json/test/F1040EZ.json", JSON.stringify(pdfData));
+        fs.writeFile("./pdf2json/test/F1040EZ.json", JSON.stringify(pdfData),(data) => { console.log(data)});
     });
 
     pdfParser.loadPDF("./pdf2json/test/pdf/fd/form/F1040EZ.pdf");