prettified post/pre scheduler json export

src/storm/storage/PostScheduler.cpp

@@ -160,7 +160,7 @@ namespace storm {
                             auto choiceOriginCorrectionJson = model->getChoiceOrigins()->getChoiceAsJson(globalChoiceCorrectionIndex);
                             std::string choiceActionLabel = choiceOriginJson["action-label"];
                             std::string choiceCorrectionActionLabel = choiceOriginCorrectionJson["action-label"];
-                            choiceOriginJson["action-label"] = choiceActionLabel.append(": ").append(choiceCorrectionActionLabel);
+                            choiceOriginJson["action-label"] = choiceActionLabel.append(": ").append(choiceCorrectionActionLabel).append("\n");
                             choiceJson["origin"] = choiceOriginJson;                            
                         }
                         if (model && model->hasChoiceLabeling()) {

src/storm/storage/PreScheduler.cpp

@@ -172,7 +172,10 @@ namespace storm {
                             if (model && model->hasChoiceOrigins() &&
                                 model->getChoiceOrigins()->getIdentifier(globalChoiceIndex) !=
                                 model->getChoiceOrigins()->getIdentifierForChoicesWithNoOrigin()) {
-                                choiceJson["origin"] = model->getChoiceOrigins()->getChoiceAsJson(globalChoiceIndex);
+                                auto choiceOriginJson = model->getChoiceOrigins()->getChoiceAsJson(globalChoiceIndex);
+                                std::string choiceActionLabel = choiceOriginJson["action-label"];
+                                choiceOriginJson["action-label"] = choiceActionLabel.append("\n");
+                                choiceJson["origin"] = choiceOriginJson;
                             }
                             if (model && model->hasChoiceLabeling()) {
                                 auto choiceLabels = model->getChoiceLabeling().getLabelsOfChoice(globalChoiceIndex);