Change UstId to UstIdNr

Elwig/Documents/Document.cshtml.cs

@@ -17,7 +17,7 @@ namespace Elwig.Documents {
             Footer = Utils.GenerateFooter("<br/>", " \u00b7 ")
                 .Item(c.NameFull).NextLine()
                 .Item(c.Address).Item($"{c.Plz} {c.Ort}").Item("Österreich").Item("Tel.", c.PhoneNr).Item("Fax", c.FaxNr).NextLine()
-                .Item(c.EmailAddress).Item(c.Website).Item("Betriebs-Nr.", c.LfbisNr).Item("UID", c.UstId).NextLine()
+                .Item(c.EmailAddress).Item(c.Website).Item("Betriebs-Nr.", c.LfbisNr).Item("UID", c.UstIdNr).NextLine()
                 .Item("BIC", c.Bic).Item("IBAN", c.Iban)
                 .ToString();
             Date = DateTime.Today;