Tweak usage of correction history
Instead of using linear formula use quadratic one. Maximum impact of
correction history is doubled this way, it breaks even with previous
formula on half of maximum value.
Passed STC:
https://tests.stockfishchess.org/tests/view/659591e579aa8af82b95d7e8
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 225216 W: 57616 L: 57019 D: 110581
Ptnml(0-2): 747, 26677, 57201, 27198, 785
Passed LTC:
https://tests.stockfishchess.org/tests/view/6596ee0b79aa8af82b95f08a
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 73314 W: 18524 L: 18125 D: 36665
Ptnml(0-2): 41, 8159, 19875, 8524, 58
closes https://github.com/official-stockfish/Stockfish/pull/4967
Bench: 1464785