Can we change the title of this to something like, "Add example of platform-specific support for negative timestamps to the time documentation"?

That might be a bit wordy, but as it is now, this looks like it's reporting a bug in dateutil, which is not part of the standard library, which may be confusing people looking for something to solve.

As for the meat of the documentation change, I think we can adapt the wording from `datetime.fromtimestamp`, which actually has a very similar example called out: https://docs.python.org/3.7/library/datetime.html#datetime.datetime.fromtimestamp

> fromtimestamp() may raise OverflowError, if the timestamp is out of the range of values supported by the platform C localtime() or gmtime() functions, and OSError on localtime() or gmtime() failure. It’s common for this to be restricted to years in 1970 through 2038.