[Config] Add phpunitNarrowAsserts and phpunitMockToStub to withPreparedSets()

[TomasVotruba]

Wires two existing rector-phpunit sets into withPreparedSets() so they can be toggled like the other prepared sets.

• PHPUnitSetList::PHPUNIT_NARROW_ASSERTS → phpunitNarrowAsserts: true
• PHPUnitSetList::PHPUNIT_MOCK_TO_STUB → phpunitMockToStub: true

Usage

return RectorConfig::configure()
    ->withPreparedSets(
        phpunitNarrowAsserts: true,
        phpunitMockToStub: true,
    );

phpunitNarrowAsserts narrows generic asserts to specific methods, e.g.:

-$this->assertEquals(10, $value);
+$this->assertSame(10, $value);

phpunitMockToStub swaps mocks with no expectations for stubs:

-$mock = $this->createMock(SomeType::class);
+$stub = $this->createStub(SomeType::class);