Fix bug where string print overrides wouldn't be used

Author: Genbox

Src/FastData.Generator/Framework/Definitions/StringTypeDef.cs

@@ -8,11 +8,21 @@ public class StringTypeDef : ITypeDef<string>
     public StringTypeDef(string name, Func<string, string>? print = null)
     {
         Name = name;
-        Print = print ?? (static x => $"\"{x}\"");
+
+        if (print != null)
+        {
+            Print = print;
+            PrintObj = x => print(x.ToString());
+        }
+        else
+        {
+            Print = static x => $"\"{x}\"";
+            PrintObj = static x => $"\"{x}\"";
+        }
     }
 
     public DataType DataType => DataType.String;
     public string Name { get; }
-    public Func<object, string> PrintObj => x => $"\"{x}\"";
+    public Func<object, string> PrintObj { get; }
     public Func<string, string> Print { get; }
 }