`Series.argmin` return type

[zmoon]

Describe the bug
I would expect Series.argmin() to have scalar integer return type, but the types seem not to match. First noticed with an error message like this:

error: Argument ... has incompatible type
"Optional[ndarray[Any, Any]]"; expected "Optional[int]"  [arg-type]

To Reproduce
Minimal example:

import pandas as pd

def f(i: int):
    print(df.iloc[i])

df = pd.DataFrame({"a": [-1, 0, 1], "b": [1, 2, 3]})
i = df.a.abs().argmin()

f(i)

> mypy t.py
t.py:9: error: Argument 1 to "f" has incompatible type "ndarray[Any, Any]"; expected "int"  [arg-type]
Found 1 error in 1 file (checked 1 source file)

Please complete the following information:

• OS: Windows
• OS Version: 10 22H2
• Python version: 3.9.13
• version of type checker: mypy 1.1.1
• version of installed pandas-stubs: 1.5.3.230321

[Dr-Irv]

That's a bug that has been there a long time since we copied over the Microsoft stubs.

Need to change:

pandas-stubs/typings/pandas/core/base.pyi

Lines 59 to 60 in 0cd7fc6

	def argmax(self, axis: Optional[SeriesAxisType] = ..., skipna: bool = ..., *args, **kwargs) -> np.ndarray: ...
	def argmin(self, axis: Optional[SeriesAxisType] = ..., skipna: bool = ..., *args, **kwargs) -> np.ndarray: ...

to return int not np.ndarray. And add tests for both.