ReflectionParameter::getPosition() is non-negative-int.
ReflectionMethod name property is always non-empty-string.
ReflectionAttribute::getTarget() returns Attribute::TARGET_* instead of int-mask. Even for attributes of promoted properties (https://3v4l.org/rpM1t).
*::getAttributes() always returns a list (https://3v4l.org/LYAMb).
Also:
* added PHP 8.2 stubs
* refined types to make impossible scenarios more clear (like `ReflectionIntersectionType#allowsNull()`)
This is a first attempt at refining these types: the structure of these stubs is quite confusing to me,
so I don't know if this approach is correct, and if the stubs are merged together, or if entire symbols
need to be completely re-declared for each PHP version.
