Fix Chess960 pseudo legality for castle moves

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 84.61538% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 87%. Comparing base (d8de9f0) to head (8b3339e).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #229 +/- ## ===================================== - Coverage 87% 87% -0% ===================================== Files 33 33 Lines 4290 4313 +23 Branches 4290 4313 +23 ===================================== + Hits 3697 3716 +19 - Misses 577 581 +4 Partials 16 16 ```

[github-actions[bot]]

Against master [hash=64; threads=1]: 🆗 Elo difference: 16.81 +/- 22.63, LOS: 92.72 %, DrawRatio: 33.83 %

[github-actions[bot]]

Against v1.5.1 [hash=64; threads=1]: 🆗 Elo difference: -13.32 +/- 21.69, LOS: 11.43 %, DrawRatio: 39.17 %

[github-actions[bot]]

Against master [hash=256; threads=4]: 🆗 Elo difference: -33.11 +/- 38.86, LOS: 4.72 %, DrawRatio: 35.50 %

[github-actions[bot]]

Against v1.5.1 [hash=256; threads=4]: 🆗 Elo difference: 1.74 +/- 35.62, LOS: 53.82 %, DrawRatio: 45.50 %