The error message for unsupported index on shift() could be more explicit
When the type of data index is not datetime-like, the following error message will raise:
`NotImplementedError: Not supported for type Index`
 
The error message could be more useful by explicitly stating which types of data that `shift` supports.
 
Expected error message:
` f"This method is only implemented for DatetimeIndex, PeriodIndex and TimedeltaIndex; Got type {type(self).__name__}."`
