TYP: Improve typing on pandas.core.algorithms.duplicated()
Per comment in PR #41985 :
https://github.com/pandas-dev/pandas/pull/41985/files/c14bca375fc1f88b0ebc3fdf9d94bab568d1066a#r672213029

PR updated the docs, which reflected that `pandas.core.algorithms.duplicated()` does accept a `Series` as an argument:
```python
>>> import pandas as pd
>>> from pandas.core.algorithms import duplicated
>>> s=pd.Series([1,2,3,4,2,3,1])
>>> duplicated(s)
array([False, False, False, False,  True,  True,  True])
```

So the input type should be updated.
