Report a data provider that provides no data sets

[SanderMuller]

EmptyDataProviderRule reports a data provider method whose every return statement returns an iterable that is provably empty. PHPUnit 10 and newer errors on this. PHPUnit 9 skipped the test.

Registered behind bleedingEdge, like DataProviderDataRule. It reports unless the detected PHPUnit major is 9 or lower, so a project where the version cannot be detected still gets the check.

Scope limits, each deliberate:

• Generators are skipped. Whether a generator yields at all depends on control flow. Where it is decidable, core already reports deadCode.unreachable on the dead yield.
• The phpstan-doctrine example in the issue is a generator guarded by PHP_VERSION_ID, which PHPStan models as int<70400, 80599>. No static check can decide it, and this rule does not report it.
• A provider declared in another class is checked when that class is analysed, not from the test method.
• With an undetectable PHPUnit version, DataProviderHelper does not read #[DataProvider], so only annotation-declared providers are covered. That is existing helper behaviour, and the test encodes it.

Infection on the changed lines generates 3 mutants. All 3 are killed by the test framework, at 100% covered MSI.

Closes #251