Fix 9aef7b8c: Don't dispatch hover event if already hovering. (#10042)

This fixes the timed tooltip window being (invisibly) destroyed and
reconstructed every frame.

This also affects the unused OnHover() window event.

src/window.cpp

@@ -2966,7 +2966,7 @@ void HandleMouseEvents()
 			hover_pos = _cursor.pos;
 			hover_time = std::chrono::steady_clock::now();
 			_mouse_hovering = false;
-		} else {
+		} else if (!_mouse_hovering) {
 			if (std::chrono::steady_clock::now() > hover_time + std::chrono::milliseconds(_settings_client.gui.hover_delay_ms)) {
 				click = MC_HOVER;
 				_input_events_this_tick++;