hle: services: TimeZoneContentManager: This can be made explicit.

src/core/hle/service/time/time_zone_content_manager.h

@@ -21,7 +21,7 @@ namespace Service::Time::TimeZone {
 
 class TimeZoneContentManager final {
 public:
-    TimeZoneContentManager(Core::System& system);
+    explicit TimeZoneContentManager(Core::System& system);
 
     void Initialize(TimeManager& time_manager);