Problem: filetype: N-Tripels and TriG files are not recognized
Solution: detect '*.nt' files as ntriples filetype and '*.trig' files
as trig filetype (Gordian Dziwis)
closes: #16493
Signed-off-by: Gordian Dziwis <gordian@dziw.is>
Signed-off-by: Christian Brabandt <cb@256bit.org>