typo

src/include/taler_error_codes.h

@@ -17,7 +17,7 @@
  * @file taler_error_codes.h
  * @brief error codes returned by GNU Taler
  *
- * This file should defines constants for error codes returned
+ * This file should define constants for error codes returned
  * in Taler APIs.  We use codes above 1000 to avoid any
  * confusing with HTTP status codes.  All constants have the
  * shared prefix "TALER_EC_" to indicate that they are error

src/include/taler_signatures.h

@@ -1084,7 +1084,18 @@ struct TALER_ContractPS
  */
 struct PaymentResponsePS
 {
+  /**
+   * Set to TALER_SIGNATURE_MERCHANT_PAYMENT_OK so far. Note that
+   * unsuccessful payments are usually proven by some exchange's signature,
+   * thus it is unlikely that a merchant needs to set a purpose other than
+   * the above mentioned
+   */
   struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
+
+  /**
+   * Hash of the contract associated with this confirmation
+   */
+  struct GNUNET_HashCode h_contract;
 };