It's really not a good idea to be syringe feeding a rabbit until a vet has ruled out bloat and a complete bowel obstruction. Reason is that if a rabbit isn't eating due to bloat, syringing more food into a bloated stomach will increase pressure on the stomach, heart, and lungs, which will result in more pain, and could cause dangerous heart and lung problems from the pressure, as well as possible risk of stomach rupture.
If it's not bloat but a complete bowel obstruction causing the lack of appetite, syringe feeding will have the same result of causing increased pressure on a bowel that isn't moving, which could result in a possible rupture.
Until these are both ruled out by a vet, syringe feeding isn't advised. That's why it's so important to get into the vet that same day. Because a rabbit shouldn't go more than 24 hours without eating adequate amounts of food, and they can't be fed until a vet has ruled out those two things, either by palpation, xray, or both.
I should also mention that when you do start syringe feeding, human baby food really isn't the best alternative food source to be feeding. Critical care mix for rabbits it the usual syringe feeding food used. It has the nutrients and fiber rabbits need for health and good gut movement. Another alternative would be a plain grass hay pellet made into a mush.
Rabbits need indigestible fiber for that digestive tract to move and function correctly. People food like processed baby food, doesn't have enough of the fiber rabbits need, and is also usually quite high in carbs and/or sugars, which is not a good thing for a rabbit to be having even in normal circumstances. So when your rabbit is seen by the vet, the vet should be sending you home with the critical care syringing mix made for sick rabbits.