C#: Implement proper generic type name printing for Godot Editor

[Delsin-Yu]

The current Godot Editor Implementation fetches a class_name directly from the System.Type.Name, which does not return the full definition of a generic type (only the generic parameter count).

This PR uses an algorithm created by @ZerxZ, @TML233, and @jinsediaoying for printing the actual underlying generic type definition.
Our tests have convinced us this algorithm is capable of handling all generic use cases, see the following comparison.
This advanced type-printing algorithm only runs when a cached boolean _isEditorHintCached reports true, (fallback to System.Type.Name otherwise), so it should not affect runtime performance (only one extra boolean check).

Before

After

These are the actual type header definitions in the scripts

public partial class ListItemComponent<TData> : Control { /*other*/ }

public partial class ComplexCrazyListItemComponent<T1, T2, T3, T4> : ListItemComponent<(int, float, (List<Func<List<Dictionary<List<int?>, List<int?[,,]>>>, List<(List<int>, List<int[]>)?>>>, List<int[,,][,][,,,,]>))?> { /*other*/ }

public partial class Test<T> : ComplexCrazyListItemComponent<int, float, GodotObject, List<int>> { /*other*/ }

public partial class Test2 : Test<GodotObject> { /*other*/ }

[Delsin-Yu]

I removed the cached StringBuilder and optimized the while(true) section; however, I think we need a consensus on whether we should cache the IsEditorHint or initialize _builtinTypeNameDictionary _tupleTypeSet by default.

I wish to minimize the performance impact on runtime by this PR, where IsEditorHint calls back to the native code base (which is expensive compared to a check on cached boolean), and two collections are never called in runtime so that I don't think we should initialize them at all.

cc @raulsntos

[raulsntos]

The .NET team discussed this and we think it's a good addition. The technical aspects look good, this is a code-style review.

[raulsntos]

Looks good to me and works as expected. Thanks!

[akien-mga]

Thanks!