The C# Interface ISerializationListener is undocumented

**Your Godot version:**

4.3

**Issue description:**

If you are using C# in your Godot project, you can implement ISerializationListener to execute code in OnBeforeSerialize and OnAfterDeserialize. These functions are called when building the C# solution, and perhaps also in other circumstances?

This feature can be helpful if you have to acount for serialization in your [Tool] scripts, but is completely [undocumented](https://docs.godotengine.org/en/stable/search.html?q=ISerializationListener&check_keywords=yes&area=default). I only found out about its existence via this informative issue: https://github.com/godotengine/godot-proposals/issues/9001

Frankly, it would be helpful if all the information in that issue was added to the documentation. [The Godot API for C# section](https://docs.godotengine.org/en/stable/tutorials/scripting/c_sharp/c_sharp_differences.html) seems like a logical place.

I can attempt to write the documentation, but I'm not particularly knowledgable about the behaviour of ISerializationListener, and even less on the entire process of rebuilding the C# solution.

**URL to the documentation page (if already existing):**
N/A