feat: update labels of voucher fields

addresses #869bf8tzv

src/Form/Service/ParticipantFieldOptionsProvider.php

@@ -430,7 +430,7 @@ class ParticipantFieldOptionsProvider extends AbstractFieldOptionsProvider
         // Purchase voucher field provider - redemption code for vouchers that apply to complete booking
         // Collected from all participants and aggregated into single <gutscheine> collection in booking payload
         $this->fieldOptionProviders['purchaseVoucherCode'] = fn (BookingDto $bookingDto, int $participantIndex, array $options = []) => [
-            'label' => 'Gutschein-Einlösecode',
+            'label' => 'Gutschein-Code',
             'required' => false,
             'attr' => [
                 'placeholder' => 'z.B. 1F7V6PADRZ',
@@ -442,7 +442,7 @@ class ParticipantFieldOptionsProvider extends AbstractFieldOptionsProvider
         // Promo voucher field provider - promo code applied per participant in booking payload
         // Included in participant XML node as <aktionscode>
         $this->fieldOptionProviders['promoVoucherCode'] = fn (BookingDto $bookingDto, int $participantIndex, array $options = []) => [
-            'label' => 'Aktionscode',
+            'label' => 'Rabatt-Code',
             'required' => false,
             'attr' => [
                 'placeholder' => 'z.B. LW0705',