Rewrite Builders to take advantage 4.2 covariance

[Pyxus]

To make the builders more pleasant to work I would rewrite the builder per class despite each builder otherwise having identical functionality. This is because it was the only way to get autocomplete support for the methods unique to each builder. However, with the new return type covariance included in Godot 4.2 I can now remedy this. The downside is Fray will only support 4.2+ now, However I believe this is fine given the pending re-release.

[Pyxus]

Solved by 2fdf608