Fix indent level bug preventing wrapper function rename

Original code intends to rename the wrapper function f using the provided name, but this isn't happening because code is incorrectly indented an extra level.

Example:
>>> from pandas.core.groupby import GroupBy
>>> GroupBy.sum.__name__
'f'

Should be 'sum'.

Author: Matt Hagy

pandas/core/groupby.py

@@ -126,7 +126,7 @@ def f(self, **kwargs):
                 result = result._convert(datetime=True)
             return result
 
-        f.__name__ = name
+    f.__name__ = name
 
     return f