Save settings when switching to new macro

This should ensure that settings are saved more frequently and less data
is lost in case the plugin crashes with the settings dialog opened.

lib/macro/macro-tab.cpp

@@ -13,6 +13,7 @@
 #include "utility.hpp"
 #include "version.h"
 
+#include <obs-frontend-api.h>
 #include <QColor>
 #include <QGraphicsOpacityEffect>
 #include <QMenu>
@@ -729,6 +730,7 @@ void AdvSceneSwitcher::MacroSelectionChanged()
 		return;
 	}
 	SetEditMacro(*macro);
+	obs_frontend_save();
 }
 
 void AdvSceneSwitcher::HighlightOnChange()