[FEAT]: Improve typing of the query builder

From discussion with Sean,
> Overall the typing discoverability could be improved (pretty easy here, these don't have return types [pyfluent/src/ansys/fluent/core/expressions/_ast.py at main · ansys/pyfluent](https://github.com/ansys/pyfluent/blob/main/src/ansys/fluent/core/expressions/_ast.py#L69-L116)) for the registry it's probably a bit harder (I think this might require a script similar to the units repo)