Unclear documentation of inplace parameter for pandas.DataFrame.rename.
#### Problem description

The documentation for pandas.DataFrame.rename currently reads

> inplace : boolean, default False
> 
> Whether to return a new DataFrame. If True then value of copy is ignored.

The sentence "Whether to return a new DataFrame" suggests that setting this parameter to True means a new DataFrame will be returned. The parameter name "inplace" suggests that setting this parameter to True means a new DataFrame will **not** be returned, which is actually the case.

The only thing in the documentation which concretely specifies the true behavior is the parameter name.

A possible alternate phrasing which suggests the correct thing would be to replace the sentence "Whether to return a new DataFrame" with something like "Modify the DataFrame, instead of returning a new DataFrame."

Same thing for the base class NDFrame and its other derived classes like Panel.