Use definition shortcode for account management server metadata

Signed-off-by: Kévin Commaille <zecakeh@tedomum.fr>

content/client-server-api/_index.md

@@ -2277,12 +2277,9 @@ in a browser.
 ##### Account management URL discovery
 
 The [OAuth 2.0 authorization server metadata](#server-metadata-discovery) is
-extended to include the following fields:
+extended to include the following **optional** fields.
 
-| Field                                  | Description                                                                                     |
+{{% definition path="schemas/oauth2-account-management-server-metadata" %}}
-|----------------------------------------|-------------------------------------------------------------------------------------------------|
-| `account_management_uri`               | The URL where the user is able to access the account management capabilities of the homeserver. |
-| `account_management_actions_supported` | An array of actions that the account management URL supports, as defined below.                 |
 
 ##### Account management URL parameters
 

data/schemas/oauth2-account-management-action.yaml

@@ -0,0 +1,9 @@
+type: string
+enum:
+  - "org.matrix.profile"
+  - "org.matrix.devices_list"
+  - "org.matrix.device_view"
+  - "org.matrix.device_delete"
+  - "org.matrix.account_deactivate"
+  - "org.matrix.cross_signing_reset"
+description: An action that the account management URL supports.

data/schemas/oauth2-account-management-server-metadata.yaml

@@ -0,0 +1,16 @@
+type: object
+title: OAuth 2.0 Server Metadata Account Management Extension
+properties:
+  account_management_uri:
+    type: string
+    format: uri
+    description: |-
+      The URL where the user is able to access the account management capabilities of the
+      homeserver.
+  account_management_actions_supported:
+    type: array
+    description: |-
+      List of [actions](/client-server-api/#account-management-url-actions) that the account
+      management URL supports.
+    items:
+      $ref: ./oauth2-account-management-action.yaml