File names aren't output correctly

[theodorejb]

Issue summary

In version 8.2, file names containing a comma could be output without issues. In version 9, the commas are replaced with a percent encoding.

System information

Information	Description
League\Csv version	9.0.1
PHP/HHVM version	7.1
OS Platform	Windows Server 2012 R2
Browser	Chrome 60

Standalone code, or other way to reproduce the problem

$csv = \League\Csv\Writer::createFromFileObject(new \SplTempFileObject());
$csv->insertOne(['Value']);
$csv->output('File name, with comma.csv');

Expected result

Downloaded file should be named File name, with comma.csv

Actual result

Downloaded file is named File name%2C with comma.csv in Chrome.
In Firefox, the downloaded file is named File%20name%2C%20with%20comma.csv
Only Internet Explorer downloads the file with the correct name.

[theodorejb]

It looks like this is the commit that broke it: 87bc1aa#diff-a88754023d30e0f85dd47cb54f5de942R319