Clarify matching statements

src/engine/cancun.md

@@ -122,11 +122,11 @@ Refer to the response for [`engine_forkchoiceUpdatedV2`](./shanghai.md#engine_fo
 
 This method follows the same specification as [`engine_forkchoiceUpdatedV2`](./shanghai.md#engine_forkchoiceupdatedv2) with the following changes to the processing flow:
 
-1. Client software **MUST** verify that `forkchoiceState` matches the expected fields and return `-32602: Invalid params` on failure.
+1. Client software **MUST** verify that `forkchoiceState` matches the [`ForkchoiceStateV1`](./paris.md#ForkchoiceStateV1) structure and return `-32602: Invalid params` on failure.
 
 2. Extend point (7) of the `engine_forkchoiceUpdatedV1` [specification](./paris.md#specification-1) by defining the following sequence of checks that **MUST** be run over `payloadAttributes`:
 
-    1. `payloadAttributes` matches the expected fields, return `-38003: Invalid payload attributes` on failure.
+    1. `payloadAttributes` matches the [`PayloadAttributesV3`](#payloadattributesv3) structure, return `-38003: Invalid payload attributes` on failure.
 
     2. `payloadAttributes.timestamp` falls within the time frame of the Cancun fork, return `-38005: Unsupported fork` on failure.