DOC: Fix pandas.Series.dt seconds, nanoseconds GL08, SA01

[KatsiarynaDzibrova]

• xref DOC: Enforce Numpy Docstring Validation | pandas.Series #58504

Fixes:
pandas.Series.dt.nanoseconds SA01
pandas.Series.dt.seconds SA01

[MarcoGorelli]

thanks @KatsiarynaDzibrova , looks like there's a test failure

_______ [doctest] pandas.core.indexes.accessors.DatetimeProperties.freq ________
394         ...         "2022-02-22 05:22:22-06:00",
395         ...         "2022-02-22 06:22:22-06:00",
396         ...         "2022-02-22 07:22:22-06:00",
397         ...         "2022-02-22 08:22:22-06:00",
398         ...         "2022-02-22 09:22:22-06:00",
399         ...         "2022-02-22 10:22:22-06:00",
400         ...         "2022-02-22 11:22:22-06:00",
401         ...     ]
402         ... )
403         >>> datetimeindex.freq
UNEXPECTED EXCEPTION: AttributeError("'Series' object has no attribute 'freq'")
Traceback (most recent call last):
  File "/home/runner/micromamba/envs/test/lib/python3.10/doctest.py", line 1350, in __run
    exec(compile(example.source, filename, "single",
  File "<doctest pandas.core.indexes.accessors.DatetimeProperties.freq[1]>", line 1, in <module>
  File "/home/runner/micromamba/envs/test/lib/python3.10/site-packages/pandas/core/generic.py", line 6066, in __getattr__
    return object.__getattribute__(self, name)
AttributeError: 'Series' object has no attribute 'freq'

[mroeschke]

Thanks @KatsiarynaDzibrova