Added ICoded.ToCodings()

Author: ewoutkramer

src/Microsoft.Health.Fhir.SpecManager/Language/CSharpFirely2.cs

@@ -1292,6 +1292,7 @@ private void WriteComponent(
             if (primaryCodeElementInfo is not null)
             {
                 _writer.WriteLineIndented($"{primaryCodeElementInfo.PropertyType} ICoded<{primaryCodeElementInfo.PropertyType}>.Code {{ get => {primaryCodeElementInfo.PropertyName}; set => {primaryCodeElementInfo.PropertyName} = value; }}");
+                _writer.WriteLineIndented($"IEnumerable<Coding> ICoded.ToCodings() => {primaryCodeElementInfo.PropertyName}.ToCodings();");
                 _writer.WriteLine(string.Empty);
             }