Assertion::inArray w/ constant array support

Should specify type to a union of the array values.

```php
$format = $_GET['foo'];

Assertion::inArray($format, [ // or Assertion::choice
    ExportFormat::FORMAT_CSV,
    ExportFormat::FORMAT_EXCEL,
]);

\PhpStan\dumpType($format); // ExportFormat::FORMAT_CSV|ExportFormat::FORMAT_EXCEL
```

