Update model docs for device components

docs/models/dcim/inventoryitem.md

@@ -2,6 +2,42 @@
 
 Inventory items represent hardware components installed within a device, such as a power supply or CPU or line card. They are intended to be used primarily for inventory purposes.
 
-Each inventory item can be assigned a functional role, manufacturer, part ID, serial number, and asset tag (all optional). A boolean toggle is also provided to indicate whether each item was entered manually or discovered automatically (by some process outside NetBox).
-
 Inventory items are hierarchical in nature, such that any individual item may be designated as the parent for other items. For example, an inventory item might be created to represent a line card which houses several SFP optics, each of which exists as a child item within the device. An inventory item may also be associated with a specific component within the same device. For example, you may wish to associate a transceiver with an interface.
+
+## Fields
+
+### Device
+
+The device in which the inventory item is installed.
+
+### Parent
+
+The parent inventory item to which this item is assigned (optional).
+
+### Name
+
+The inventory item's name. Must be unique to the parent device.
+
+### Label
+
+An alternative physical label identifying the inventory item.
+
+### Role
+
+The functional [role](./inventoryitemrole.md) assigned to this inventory item.
+
+### Manufacturer
+
+The [manufacturer](./manufacturer.md) that produced the item.
+
+### Part ID
+
+The part identification or model number assigned by the manufacturer.
+
+### Serial Number
+
+The serial number assigned by the manufacturer.
+
+### Asset Tag
+
+A unique, locally-administered label used to identify hardware resources.