tauRecTools: style fix for CombinedP4FromRecoTaus (ATLTAU-1729)
In this MR, we refactor the CombinedP4FromRecoTaus a bit to make further development easier
- use a consistent naming convention
- instead of check the decay mode here and there, we only check it once in the public interface
- instead of setting the intermediate results here and there, we do it in one function
- add comments for better readability
- ...
I have a bunch of questions related to the implementation, but they will be fixed in a follow-up. Here, I only focus on the coding style.
Edited by Xiaozhong Huang