[python] add type hints on sklearn metric and eval wrappers (#5238)
[python] add type hints on sklearn metric and eval wrappers (#5238)


henry0312/LightGBM,microsoft/LightGBM,microsoft/LightGBM,henry0312/LightGBM,henry0312/LightGBM,microsoft/LightGBM,henry0312/LightGBM,henry0312/LightGBM,microsoft/LightGBM,microsoft/LightGBM