Series.replace and DataFrame.replace have same docstring?
```
In [4]: pd.__version__
Out[4]: u'0.18.1'
```

The docstring for Series.replace refers to looking up column names, which AFAIK doesn't make sense for the Series version of `replace`.  It seems like the Series function is just blindly inheriting the DataFrame docstring?

http://pandas.pydata.org/pandas-docs/stable/generated/pandas.Series.replace.html?highlight=replace#pandas.Series.replace

http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.replace.html?highlight=replace#pandas.DataFrame.replace

For example, the following trivial example of `Series.replace()` does not agree with the docstring:

```
import pandas as pd

x = pd.DataFrame([dict(A=1, B=2, C=3), dict(A=2, B=3, C=4), dict(A=3, B=4, C=5)])

print(x.A.replace({1:0}))
print(x.A)

0    0
1    2
2    3
Name: A, dtype: int64
0    1
1    2
2    3
Name: A, dtype: int64
```
