lnrpc: fix docs on ListPaymentsRequest

lnrpc/lightning.proto

@@ -4138,11 +4138,11 @@ message ListPaymentsRequest {
     */
     bool count_total_payments = 5;
 
-    // If set, returns all invoices with a creation date greater than or equal
+    // If set, returns all payments with a creation date greater than or equal
     // to it. Measured in seconds since the unix epoch.
     uint64 creation_date_start = 6;
 
-    // If set, returns all invoices with a creation date less than or equal to
+    // If set, returns all payments with a creation date less than or equal to
     // it. Measured in seconds since the unix epoch.
     uint64 creation_date_end = 7;
 }