LibCore: Add Timer::create_repeating convenience method

Author: https://github.com/tomuta
Commit: 7269e0f751
Pull-request: https://github.com/SerenityOS/serenity/pull/5988
Reviewed-by: https://github.com/awesomekling

Userland/Libraries/LibCore/Timer.h

@@ -35,6 +35,12 @@ class Timer final : public Object {
     C_OBJECT(Timer);
 
 public:
+    static NonnullRefPtr<Timer> create_repeating(int interval, Function<void()>&& timeout_handler, Object* parent = nullptr)
+    {
+        auto timer = adopt(*new Timer(interval, move(timeout_handler), parent));
+        timer->stop();
+        return timer;
+    }
     static NonnullRefPtr<Timer> create_single_shot(int interval, Function<void()>&& timeout_handler, Object* parent = nullptr)
     {
         auto timer = adopt(*new Timer(interval, move(timeout_handler), parent));