Clarify udev rule addition.
Clarify udev rule addition.

It is important to note that the udev rule should be added to a file that will
be lexicographically near the end of the sorted rules files so it is not
overridden by other rules.

matt-leach/python-ant-downloader,braiden/python-ant-downloader,braiden/python-ant-downloader,matt-leach/python-ant-downloader