Add new food item: Jujube

I want to suggest adding jujube as a new food item. Jujubes grow on small jujube trees that spawn in plains and forest biomes. Eating jujubes restores 2 hunger points. Players can collect saplings to plant jujube trees anywhere. The model and texture of jujube are simple, with lightweight resources. This new fruit can enrich the survival food system for all players.