docs(policies): adapt to new json schema with "allow" key mandatory

Author: brunobuddy

access-policies.md

@@ -48,12 +48,12 @@ In this case, everyone can see the **Invoice** items, only logged-in **Users** c
 
 There are 4 possible access types:
 
-| Access         | Description                                                                                                                                                                                                                                                          | Short version (emoji) |
-| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------- |
-| **public**     | Everyone has access                                                                                                                                                                                                                                                  | 🌐                    |
-| **restricted** | Only logged-in users have access to it. If _allow_ key specifies one or several entities, users logged in as other entities will not have access. If _condition_ is set to `self`, it limits access to the item owner. Admins always have access to restricted rules | 🔒                    |
-| **admin**      | Only [admins](./auth.md#admins) have access                                                                                                                                                                                                                          | 👨🏻‍💻                    |
-| **forbidden**  | No one has access, not even admins                                                                                                                                                                                                                                   | 🚫                    |
+| Access         | Description                                                                                                                                                                                                                                                                                                        | Short version (emoji) |
+| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | --------------------- |
+| **public**     | Everyone has access                                                                                                                                                                                                                                                                                                | 🌐                    |
+| **restricted** | Only logged-in users have access to it. The _allow_ key must be used to specify one or several [authenticable entities](./auth.md#authenticable-entities) that will have access to the content. If _condition_ is set to `self`, it limits access to the item owner. Admins always have access to restricted rules | 🔒                    |
+| **admin**      | Only [admins](./auth.md#admins) have access                                                                                                                                                                                                                                                                        | 👨🏻‍💻                    |
+| **forbidden**  | No one has access, not even admins                                                                                                                                                                                                                                                                                 | 🚫                    |
 
 ### Entity rules