BUG: Timedelta repr doesn't show nano

[ghost]

xref #9309, though that's about consistency, not just missing info.

In [7]: pd.Timedelta(nanoseconds=1)
Out[7]: Timedelta('0 days 00:00:00.000000')

In [8]: pd.Timestamp("2000-01-01")-pd.Timedelta(nanoseconds=1)
Out[8]: Timestamp('1999-12-31 23:59:59.999999999')

@jorisvandenbossche, recall we discussed using "roles" for repr? this might be a good use case, considering #9309 (comment).

[jorisvandenbossche]

Closing as a duplicate, and renamed #9309 to make it clear that it is about timedelta no showing nanoseconds

recall we discussed using "roles" for repr? this might be a good use case, considering #9309 (comment).

Yes, although here it is more related to the fact that for Series/Index we need to define the resolution for the full series, not per formatting the individual scalars (which is already what is happening right now, but it would be good to generalize this for EAs).