Drop obsolete code

Author: PowerKiKi

src/PhpSpreadsheet/Writer/Xls/Workbook.php

@@ -2,7 +2,6 @@
 
 namespace PhpOffice\PhpSpreadsheet\Writer\Xls;
 
-use PHP_CodeSniffer\Tokenizers\PHP;
 use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
 use PhpOffice\PhpSpreadsheet\Cell\Coordinate;
 use PhpOffice\PhpSpreadsheet\DefinedName;