[PHPUnit60] Add DoesNotPerformAssertions attribute directly and skip traits

[TomasVotruba]

Two changes to AddDoesNotPerformAssertionToNonAssertingTestRector:

1) Add the attribute directly, when it exists

If PHPUnit\Framework\Attributes\DoesNotPerformAssertions is available (PHPUnit 10+), the attribute is added instead of the annotation. Projects on older PHPUnit keep getting the docblock annotation.

 final class SomeTest extends TestCase
{
- public function test()+ #[\PHPUnit\Framework\Attributes\DoesNotPerformAssertions]+ public function test()
{
$nothing = 5;
}
}

Previously this always produced:

/** * @doesNotPerformAssertions */

2) Skip traits

A trait method has no owning class, so there is no way to tell whether the class using it asserts elsewhere. Adding the attribute there can silence a real assertion check.

trait SomeNonAssertingTrait
{
// left as ispublicfunctiontestSomething()
{
$nothing = 5;
}
}