DOC: Run doctests over pandas directory

[mroeschke]

• closes DOC: ongoing fixing of doctests #22459

--ignore-glob="**/test_*.py" is necessary or else unit tests are collected and run

% pytest --doctest-modules pandas --collect-only ... <Function test_rolling_consistency_var_debiasing_factors[all_data16-rolling_consistency_cases0-False]> <Function test_rolling_consistency_var_debiasing_factors[all_data16-rolling_consistency_cases1-True]> <Function test_rolling_consistency_var_debiasing_factors[all_data16-rolling_consistency_cases1-False]> <Function test_rolling_consistency_var_debiasing_factors[all_data17-rolling_consistency_cases0-True]> <Function test_rolling_consistency_var_debiasing_factors[all_data17-rolling_consistency_cases0-False]> <Function test_rolling_consistency_var_debiasing_factors[all_data17-rolling_consistency_cases1-True]> <Function test_rolling_consistency_var_debiasing_factors[all_data17-rolling_consistency_cases1-False]> <Package tseries> <DoctestModule frequencies.py> <DoctestItem pandas.tseries.frequencies.infer_freq> <DoctestModule holiday.py> <DoctestItem pandas.tseries.holiday.Holiday.__init__> <Package util> <DoctestModule _decorators.py> <DoctestItem pandas.util._decorators.deprecate_kwarg> <DoctestModule _validators.py> <DoctestItem pandas.util._validators.validate_axis_style_args> =================================================================== 153109 tests collected in 46.60s ===================================================================