backport of ContractReferencedDocument element ordering

Author: stephanstapel

ZUGFeRD/InvoiceDescriptor20Writer.cs

@@ -225,6 +225,8 @@ public override void Save(InvoiceDescriptor descriptor, Stream stream, ZUGFeRDFo
                 {
                     _Writer.WriteStartElement("ram", "ContractReferencedDocument", Profile.Extended);
 
+                    _Writer.WriteOptionalElementString("ram", "IssuerAssignedID", tradeLineItem.ContractReferencedDocument.ID);
+
                     // reference to the contract position
                     _Writer.WriteOptionalElementString("ram", "LineID", tradeLineItem.ContractReferencedDocument.LineID);
 
@@ -236,8 +238,7 @@ public override void Save(InvoiceDescriptor descriptor, Stream stream, ZUGFeRDFo
                         _Writer.WriteValue(_formatDate(tradeLineItem.ContractReferencedDocument.IssueDateTime.Value));
                         _Writer.WriteEndElement(); // !udt:DateTimeString
                         _Writer.WriteEndElement(); // !ram:IssueDateTime
-                    }
-                    _Writer.WriteOptionalElementString("ram", "IssuerAssignedID", tradeLineItem.ContractReferencedDocument.ID);
+                    }                    
 
                     _Writer.WriteEndElement(); // !ram:ContractReferencedDocument(Extended)
                 }