GH 9273: Timedelta constructor should accept nanoseconds keyword.

[tvyomkesh]

closes #9273

This patch adds nanoseconds keyword support in Timedelta constructor.

In [1]: from pandas import Timedelta

In [2]: td = Timedelta(nanoseconds=1)

In [3]: td1 = Timedelta(microseconds=1)

In [4]: td.components
Out[4]: Components(days=0, hours=0, minutes=0, seconds=0, milliseconds=0, microseconds=0, nanoseconds=1)

In [5]: (td + td1).components
Out[5]: Components(days=0, hours=0, minutes=0, seconds=0, milliseconds=0, microseconds=1, nanoseconds=1)

[jreback]

this is a nitpick - I think the following is better

nano = kwargs.pop('nanoseconds',0)
value = convert_to_timedelta64(timedelta(**kwargs),'ns',False) + nano

[tvyomkesh]

ok fine. done.

[jreback]

minor comment. ping when you have pushed

[tvyomkesh]

yes, much better that way. done. thanks.

[jreback]

thanks!