Example serializer from the Strawberry Shake documentation doesn't work

Product

Strawberry Shake

Version

13.9.14

Link to minimal reproduction

https://filebin.net/gs6gkxscspus013d/GraphQlSerializerIssue.zip

Steps to reproduce

1. Go to https://chillicream.com/docs/strawberryshake/v13/scalars#any-or-json
2. Copy the example serializer:

public class MyJsonSerializer : ScalarSerializer<JsonElement, object>
{
    public MyJsonSerializer(string typeName = BuiltInScalarNames.Any)
        : base(typeName)
    {
    }
    public override object Parse(JsonElement serializedValue)
    {
        // handle the serialization of the JsonElement
    }
    protected override JsonElement Format(object runtimeValue)
    {
        // handle the serialization of the runtime representation in case
        // the scalar is used as a variable.
    }
}

4. Paste in a new class
5. You'll get an error on protected override JsonElement Format(object runtimeValue)
6. It is impossible to implement this method; it gives compiler error CS0462 since it tries to override two methods:
   protected abstract TSerialized Format(TRuntime runtimeValue);
   public object? Format(object? runtimeValue)

What is expected?

A working example

What is actually happening?

Compiler error

Relevant log output

No response

Additional context

No response

Start with the Strawberry Shake v13 “Any or JSON” documentation page and the linked minimal reproduction, then inspect the shown ScalarSerializer example and its compiler error. Confirm the documented serializer example compiles without CS0462 and that the corrected example still demonstrates the intended serialization behavior.