[PHP] Add option to generate native PHP 8.1 enums

[Manueljlin]

PHP 8.1 added native enums, so instead of having

class SituationType
{
    const Unknown = 0;
    const SecurityAlert = 1;
    const EmergencyServicesCall = 2;
    const PoliceActivity = 3;
    const PoliceOrder = 4;
    const Fire = 5;
    const CableFire = 6;
    //...

    private static $names = array(
        SituationType::Unknown=>"Unknown",
        SituationType::SecurityAlert=>"SecurityAlert",
        SituationType::EmergencyServicesCall=>"EmergencyServicesCall",
        SituationType::PoliceActivity=>"PoliceActivity",
        SituationType::PoliceOrder=>"PoliceOrder",
        SituationType::Fire=>"Fire",
        SituationType::CableFire=>"CableFire",
        //...
    );

    public static function Name($e)
    {
        if (!isset(self::$names[$e])) {
            throw new \Exception();
        }
        return self::$names[$e];
    }
}

SituationType::Name(e: SituationType::CableFire); // "CableFire"
SituationType::CableFire; // 6

it's now possible to do

enum SituationType : int
{
    case Unknown = 0;
    case SecurityAlert = 1;
    case EmergencyServicesCall = 2;
    case PoliceActivity = 3;
    case PoliceOrder = 4;
    case Fire = 5;
    case CableFire = 6;
    //...
}

SituationType::CableFire->name; // "CableFire"
SituationType::CableFire->value; // 6

foreach (Status::cases() as $case) {
    echo "name {$case->name}, value {$case->value}\n";
}

this might be worth looking into? php 8.0 is already eol