Chess engine: Stockfish 19102601

Stockfish - UCI chess engine
Interesting compiled by Joost VandeVondele

Refactor final stats updates. 

This PR refactors update_quiet_stats, update_capture_stats and search to more clearly reflect what is actually done. 

Effectively, all stat updates that need to be done after search is finished and a bestmove is found, are collected in a new function ```final_stats_update()```. This shortens our main search routine, and simplifies ```update_quiet_stats```. 
The latter function is now more easily reusable with fewer arguments, as the handling of ```quietsSearched``` is only needed in ```final_stats_update```. 
```update_capture_stats```, which was only called once is now integrated in ```final_stats_update```, which allows for removing a branch and reusing some ```stat_bonus``` calls. The need for refactoring was also suggested by the fact that the comments of ```update_quiet_stats``` and ```update_capture_stats``` were incorrect (e.g. ```update_capture_stats``` was called, correctly, also when the bestmove was a quiet and not a capture). 

passed non-regression STC: 
LLR: 2.96 (-2.94,2.94) [-3.00,1.00] 
Total: 75196 W: 16364 L: 16347 D: 42485 Elo +0.08



The diff is most easily readable as ```git diff master --patience``` 

Rating JCER=3386

Stockfish 19102601 - download