docs: document the real createspendauthsig payload

TRON's SpendAuthSigParameters proto takes ask, tx_hash, and alpha and
the endpoint returns a BytesMessage value, so the request schema and
examples now match what the node actually accepts.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: SahilAujla

src/openapi/tron-http/tron-http.yaml

@@ -3157,7 +3157,7 @@ paths:
   /wallet/createspendauthsig:
     post:
       summary: Create spend authorization signature
-      description: Creates a spend authorization signature for a shielded transaction using a secret key and message data.
+      description: Creates a spend authorization signature for a shielded transaction from the spend authorizing key, the transaction hash, and the random scalar alpha.
       tags:
         - Tron HTTP API Endpoints
       requestBody:
@@ -3167,20 +3167,23 @@ paths:
             schema:
               type: object
               properties:
-                sk:
+                ask:
                   type: string
-                data:
+                tx_hash:
+                  type: string
+                alpha:
                   type: string
             example:
-              sk: "secret_key"
-              data: "message_to_sign"
+              ask: "spend_authorizing_key"
+              tx_hash: "transaction_hash"
+              alpha: "random_scalar"
       responses:
         "200":
           description: Spend authorization signature created
           content:
             application/json:
               example:
-                signature: "signed_data"
+                value: "signature_bytes"
 
   /wallet/gettriggerinputforshieldedtrc20contract:
     post: