[CodeQuality] Add PHPUNIT_NARROW_ASSERTS set focused on narrowing broad asserts to specific methods

[TomasVotruba]

Adds a focused PHPUNIT_NARROW_ASSERTS set that groups only the rules narrowing broad asserts into specific, more descriptive PHPUnit methods.

Handy when you want the assert-narrowing cleanups without adopting the full PHPUNIT_CODE_QUALITY set (mock/stub rewrites, type declarations, etc). All rules stay in PHPUNIT_CODE_QUALITY too.

use Rector\Config\RectorConfig;
use Rector\PHPUnit\Set\PHPUnitSetList;

return RectorConfig::configure()
    ->withSets([
        PHPUnitSetList::PHPUNIT_NARROW_ASSERTS,
    ]);

Example changes the set produces:

-$this->assertTrue(isset($array['key']));
+$this->assertArrayHasKey('key', $array);

-$this->assertSame(10, count($items));
+$this->assertCount(10, $items);

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

-$this->assertSame(null, $value);
+$this->assertNull($value);

Rules included (13): AssertCompareOnCountableWithMethodToAssertCount, AssertComparisonToSpecificMethod, AssertNotOperator, AssertTrueFalseToSpecificMethod, AssertSameBoolNullToSpecificMethod, AssertFalseStrposToContains, AssertIssetToSpecificMethod, AssertInstanceOfComparison, AssertEmptyNullableObjectToAssertInstanceof, AssertEqualsToSame, AssertSameTrueFalseToAssertTrueFalse, MatchAssertSameExpectedType, AssertArrayCastedObjectToAssertSame.