Adjust cancellation spec to link to tasks spec for task cancellation

Author: LucaButBoring

docs/specification/draft/basic/utilities/cancellation.mdx

@@ -34,16 +34,17 @@ notification containing:
 1. Cancellation notifications **MUST** only reference requests that:
    - Were previously issued in the same direction
    - Are believed to still be in-progress
-2. The `initialize` request **MUST NOT** be cancelled by clients
-3. Receivers of cancellation notifications **SHOULD**:
+1. The `initialize` request **MUST NOT** be cancelled by clients
+1. For [task-augmented requests](./tasks), the `tasks/cancel` request **MUST** be used instead of the `notifications/cancelled` notification. Tasks have their own dedicated cancellation mechanism that returns the final task state.
+1. Receivers of cancellation notifications **SHOULD**:
    - Stop processing the cancelled request
    - Free associated resources
    - Not send a response for the cancelled request
-4. Receivers **MAY** ignore cancellation notifications if:
+1. Receivers **MAY** ignore cancellation notifications if:
    - The referenced request is unknown
    - Processing has already completed
    - The request cannot be cancelled
-5. The sender of the cancellation notification **SHOULD** ignore any response to the
+1. The sender of the cancellation notification **SHOULD** ignore any response to the
    request that arrives afterward
 
 ## Timing Considerations