Apply php-cs-fixer style fixes to pivot table files

Shorten @see references to unqualified class names and drop a stray blank
line after the sample header docblock, matching the project's php-cs-fixer
and phpcs rules.

samples/PivotTable/02_PivotTable_Page_Filter.php

@@ -6,7 +6,6 @@ use PhpOffice\PhpSpreadsheet\Worksheet\PivotTable\PivotTableBuilder;
 
 require __DIR__ . '/../Header.php';
 /** @var PhpOffice\PhpSpreadsheet\Helper\Sample $helper */
-
 $helper->log('Create new Spreadsheet object');
 $spreadsheet = new Spreadsheet();
 $spreadsheet->getProperties()->setTitle('PhpSpreadsheet PivotTable Page Filter Sample');

samples/PivotTable/03_PivotTable_Grouping.php

@@ -7,7 +7,6 @@ use PhpOffice\PhpSpreadsheet\Worksheet\PivotTable\PivotTableBuilder;
 
 require __DIR__ . '/../Header.php';
 /** @var PhpOffice\PhpSpreadsheet\Helper\Sample $helper */
-
 $helper->log('Create new Spreadsheet object');
 $spreadsheet = new Spreadsheet();
 $spreadsheet->getProperties()->setTitle('PhpSpreadsheet PivotTable Grouping Sample');

src/PhpSpreadsheet/Worksheet/PivotTable/PivotCacheDefinition.php

@@ -9,7 +9,7 @@ namespace PhpOffice\PhpSpreadsheet\Worksheet\PivotTable;
  * worksheet and range) and the list of fields available from that source. A
  * single cache can be shared by more than one pivot table.
  *
- * @see \PhpOffice\PhpSpreadsheet\Worksheet\PivotTable\PivotTable
+ * @see PivotTable
  */
 class PivotCacheDefinition
 {

src/PhpSpreadsheet/Worksheet/PivotTable/PivotField.php

@@ -9,7 +9,7 @@ namespace PhpOffice\PhpSpreadsheet\Worksheet\PivotTable;
  * pivot table: which axis it is placed on (row, column, page/filter or data),
  * and, for value fields, which aggregation function is applied.
  *
- * @see \PhpOffice\PhpSpreadsheet\Worksheet\PivotTable\PivotTable
+ * @see PivotTable
  */
 class PivotField
 {

src/PhpSpreadsheet/Worksheet/PivotTable/PivotFieldGroup.php

@@ -15,7 +15,7 @@ namespace PhpOffice\PhpSpreadsheet\Worksheet\PivotTable;
  * The grouping is emitted into the pivot cache definition; when the workbook is
  * opened, the spreadsheet application applies it while refreshing the pivot.
  *
- * @see \PhpOffice\PhpSpreadsheet\Worksheet\PivotTable\PivotTableBuilder
+ * @see PivotTableBuilder
  */
 class PivotFieldGroup
 {

src/PhpSpreadsheet/Worksheet/PivotTable/PivotTable.php

@@ -14,8 +14,8 @@ use Stringable;
  * render the pivot, and it does not modify the underlying file - existing pivot
  * tables are still written back verbatim from the preserved source XML.
  *
- * @see \PhpOffice\PhpSpreadsheet\Worksheet\PivotTable\PivotCacheDefinition
- * @see \PhpOffice\PhpSpreadsheet\Worksheet\PivotTable\PivotField
+ * @see PivotCacheDefinition
+ * @see PivotField
  */
 class PivotTable implements Stringable
 {