Add some type hints

[spider-man-tm]

close #442

Thanks to your project, I was able to write an analytical report on baseball! Thank you very much.

I have added information about Python type hints in several places. Although the current mypy errors in the tests are not completely resolved, they are somewhat reduced.

local test results

================================== test session starts ==================================
platform darwin -- Python 3.11.4, pytest-8.3.1, pluggy-1.5.0
rootdir: /Users/takayoshi/repos/pybaseball
configfile: pytest.ini
plugins: cov-5.0.0, xdist-3.6.1
collected 130 items

tests/pybaseball/analysis/projections/marcels/test_age.py .                       [  0%]
tests/pybaseball/analysis/projections/marcels/test_marcels_batting.py .           [  1%]
tests/pybaseball/analysis/projections/marcels/test_marcels_pitching.py .          [  2%]
tests/pybaseball/analysis/trajectories/batted_balls/test_batted_balls_utils.py .. [  3%]
....                                                                              [  6%]
tests/pybaseball/analysis/trajectories/batted_balls/test_calculator.py ...        [  9%]
tests/pybaseball/analysis/trajectories/batted_balls/test_parameters.py .          [ 10%]
tests/pybaseball/cache/test_cache.py ...........                                  [ 18%]
tests/pybaseball/cache/test_cache_config.py .............                         [ 28%]
tests/pybaseball/cache/test_cache_record.py ......                                [ 33%]
tests/pybaseball/cache/test_dataframe_utils.py ......                             [ 37%]
tests/pybaseball/cache/test_func_utils.py ..                                      [ 39%]
tests/pybaseball/datahelpers/test_column_mapper.py ..                             [ 40%]
tests/pybaseball/datahelpers/test_postprocessing.py ................              [ 53%]
tests/pybaseball/datahelpers/test_singleton.py ...                                [ 55%]
tests/pybaseball/datahelpers/test_statcast_utils.py ..                            [ 56%]
tests/pybaseball/datahelpers/test_transform.py ...                                [ 59%]
tests/pybaseball/datasources/test_fangraphs.py ..........                         [ 66%]
tests/pybaseball/datasources/test_html_table.py ....                              [ 70%]
tests/pybaseball/test_amateur_draft.py ..                                         [ 71%]
tests/pybaseball/test_amateur_draft_by_team.py ..                                 [ 73%]
tests/pybaseball/test_batting_leaders.py .                                        [ 73%]
tests/pybaseball/test_league_batting_stats.py ..                                  [ 75%]
tests/pybaseball/test_league_pitching_stats.py ....                               [ 78%]
tests/pybaseball/test_pitching_leaders.py .                                       [ 79%]
tests/pybaseball/test_plotting.py ..                                              [ 80%]
tests/pybaseball/test_statcast.py .                                               [ 81%]
tests/pybaseball/test_statcast_batter.py .                                        [ 82%]
tests/pybaseball/test_statcast_pitching_spin.py ..                                [ 83%]
tests/pybaseball/test_team_batting.py .                                           [ 84%]
tests/pybaseball/test_team_fielding.py .                                          [ 85%]
tests/pybaseball/test_team_pitching.py .                                          [ 86%]
tests/pybaseball/test_teamid_lookup.py ............                               [ 95%]
tests/pybaseball/test_utils.py ......                                             [100%]

=================================== warnings summary ====================================
tests/pybaseball/test_statcast_pitching_spin.py::test_individual_calculations
  /Users/takayoshi/repos/pybaseball/.venv/lib/python3.11/site-packages/pandas/core/arrays/masked.py:582: RuntimeWarning: invalid value encountered in arccos
    result = getattr(ufunc, method)(*inputs2, **kwargs)

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
============================ 130 passed, 1 warning in 8.78s =============================