I'm pretty sure its equipment because villagers traded it to me so if I crafted it, it would be items
 
Steps to Reproduce:

1. get money
2. find farmer villager
3. trade money for pumpkin pie.
4. Hover over Pumpkin Pie in inventory

Observed behavior
Shows category of "Equipment"
Expected behavior
Category should be "Items"

Edit: it happens on Bread and Cake (I'm not sure if it actually happens on Cake this is just memory because I have no proof of remembering)