Updated series documentation to close #35406
- [x ] closes #35406
- [x ] tests added / passed
- [ x] passes `black pandas`
- [ x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Not sure how to do whatsnew entry for this - first contribution! Do let me know how to improve.

Output of scripts/validate_docstring.py: 
```
################################################################################
########################## Docstring (pandas.Series)  ##########################
################################################################################

One-dimensional ndarray with axis labels (including time series).

Labels need not be unique but must be a hashable type. The object
supports both integer- and label-based indexing and provides a host of
methods for performing operations involving the index. Statistical
methods from ndarray have been overridden to automatically exclude
missing data (currently represented as NaN).

Operations between Series (+, -, /, *, **) align values based on their
associated index values-- they need not be the same length. The result
index will be the sorted union of the two indexes.

Parameters
----------
data : array-like, Iterable, dict, or scalar value
    Contains data stored in Series.

    .. versionchanged:: 0.23.0
       If data is a dict, argument order is maintained for Python 3.6
       and later.

index : array-like or Index (1d)
    Values must be hashable and have the same length as `data`.
    Non-unique index values are allowed. Will default to
    RangeIndex (0, 1, 2, ..., n) if not provided. If data is dict-like
    and index is None, then the values in the index are used to
    reindex the Series after it is created using the keys in the data.
dtype : str, numpy.dtype, or ExtensionDtype, optional
    Data type for the output Series. If not specified, this will be
    inferred from `data`.
    See the :ref:`user guide <basics.dtypes>` for more usages.
name : str, optional
    The name to give to the Series.
copy : bool, default False
    Copy input data.

################################################################################
################################## Validation ##################################
################################################################################

3 Errors found:
        Parameters {'fastpath'} not documented
        See Also section not found
        No examples section found
```
cc @TomAugspurger  Thanks!