[Feature Request]: Add support for timeDelta.totalNanoseconds to the Time module

[lydia-duncan]

Summary of Feature

Description:
#26798 will add a totalMicroseconds method to go alongside the already-existing totalSeconds method on the timeDelta class. There's probably some use for totalNanoseconds as well, though note that nanoseconds are smaller than microseconds and microseconds are the smallest unit we store on the timeDelta type today.

Is this issue currently blocking your progress?
no, it just came up as a similarly missing feature

Code Sample

use Time;

var a = new timeDelta(microseconds=10);
writeln(a.totalNanoseconds()); // Should print 10000