ENH: Behaviour Series.isin with dataframe comparison is confusing [for discussion]
Right now we can compare a Series with a DataFrame through `Series.isin`, but is this expected / wanted behaviour? 
I would say this should raise, since expectations can be pretty ambiguous here and is confusing to me.

Also the [documentation](https://pandas.pydata.org/docs/reference/api/pandas.Series.isin.html) right now states that the `values` parameter should be "set or list-like"

Code example:

```python
values = list("ABCD")
s = pd.Series(values)
df = pd.DataFrame({"Column": values})

print(s)
0    A
1    B
2    C
3    D
dtype: object

print(df)
  Column
0      A
1      B
2      C
3      D
```
```python
# comparing DataFrame to Series, this is okay (right?) and I understand the result
df.isin(s)

   Column
0    True
1    True
2    True
3    True


#  comparing a series to df, what do we expect here? Should this raise? Why do you want to compare a Series to a DataFrame?
s.isin(df)

0    False
1    False
2    False
3    False
dtype: bool
```

Proposal: when passing anything else than "set or list-like" should raise in `Series.isin`