Update node property documentation

Author: jakezatecky

README.md

@@ -108,11 +108,11 @@ All node objects **must** have a unique `value`. This value is serialized into t
 
 Individual nodes within the `nodes` property can have the following structure:
 
-| Property    | Type   | Description                     |
-| ----------- | ------ | ------------------------------- |
-| `label`     | mixed  | **Required**. The node's label. |
-| `value`     | mixed  | **Required**. The node's value. |
-| `children`  | array  | An array of child nodes.        |
-| `className` | string | A className to add to the node. |
-| `disabled`  | bool   | Disable node.                   |
-| `icon`      | mixed  | A custom icon for the node.     |
+| Property    | Type   | Description                          |
+| ----------- | ------ | ------------------------------------ |
+| `label`     | mixed  | **Required**. The node's label.      |
+| `value`     | mixed  | **Required**. The node's value.      |
+| `children`  | array  | An array of child nodes.             |
+| `className` | string | A className to add to the node.      |
+| `disabled`  | bool   | Whether the node should be disabled. |
+| `icon`      | mixed  | A custom icon for the node.          |