076eb6f6af
A negative line number given on the command line counts from the end of the relevant file (-1 meaning the first line from the bottom), and a negative column number from the end of the relevant line. The feature was added in version 2.8.5 but not mentioned in the manual. This addresses https://savannah.gnu.org/bugs/?57342. Suggested-by: Andreas Schamanek <schamane@fam.tuwien.ac.at>