Missing tween.tween_await C# documentation

**Your Godot version:** 4.7.beta1.mono

**Issue description:** New tween_await method added has no documentation about usage in C#.

`Tween.TweenAwait(Signal signal)` is present in the C# API, but at least as far as I understand `Signal` can't be used in C# for a parameter like that, so clarity on how this is meant to be used would be very helpful. Or at least a note that it isn't usable in C# if that's the case.

The GDScript documentation was added [here](https://github.com/godotengine/godot/commit/94f9b87063713819ce2268221ee33fcf60420aca) (relevant PR [here](https://github.com/godotengine/godot/pull/79712)).

**URL to the documentation page:** https://docs.godotengine.org/en/latest/classes/class_tween.html#class-tween-method-tween-await