Add `DataSet` attribute

[roxblnfk]

Summary

Inline data for parameterized tests without separate provider method.

Feature

#[DataSet([1, 'a'])]
#[DataSet([2, 'b'])]
#[DataSet([3, 'c'])]
public function testMethod(int $number, string $letter) {}

Dataset	$number	$letter
0	1	a
1	2	b
2	3	c

Named datasets

#[DataSet('first', [1, 'a'])]
#[DataSet('second', [2, 'b'])]
public function testMethod(int $number, string $letter) {}

Datasets: first, second

Combined with DataProvider

#[DataProvider('commonCases')]
#[DataSet('edge', [0, ''])]
public function testMethod(int $number, string $letter) {}

Notes

• Empty args #[DataSet([])] → Dataset without arguments (default values will be used)

Future Scope

• Support in #[DataZip] and #[DataCross] combinators