Double fill-element in style.xml

[klafah]

This is:

- [x ] a bug report
- [ ] a feature request
- [ ] **not** a usage question (ask them on https://stackoverflow.com/questions/tagged/phpspreadsheet or https://gitter.im/PHPOffice/PhpSpreadsheet)

What is the expected behavior?

Correct representation of calculated Cells

What is the current behavior?

Numbers are 'printed' on each other (at least in MS Excel 2010, 14.0.7224.5000 32-bit)

What are the steps to reproduce?

Take a new empty excel document. Open and save it whith PhPSpreadsheet.
After that fills-section in styles.xml looks like that (double patternType "none"):
<fills count="3">
<fill><patternFill patternType="none"/></fill>
<fill><patternFill patternType="gray125"><fgColor rgb="FFFFFFFF"/> ... </fill>
<fill><patternFill patternType="none"/></fill>
</fills>

As a result, Excel no longer correctly displays cells containing formulas. Instead, the numbers are printed on top of each other.

Please provide a Minimal, Complete, and Verifiable example of code that exhibits the issue without relying on an external Excel file or a web server:

`<?php

require DIR . '/vendor/autoload.php';

// Create new Spreadsheet object
// $spreadsheet = new \PhpOffice\PhpSpreadsheet\Spreadsheet();

// add code that show the issue here...
$reader = new \PhpOffice\PhpSpreadsheet\Reader\Xlsx();
$spreadsheet = $reader->load('empty.xlsx');

$writer = new Xlsx($spreadsheet);
$writer->save('empty_modified.xlsx');`

Which versions of PhpSpreadsheet and PHP are affected?

1.8.2

[MarkBaker]

resolved in master