git-ls-files.txt: clarify what "other files" mean for --other

Signed-off-by: NMatthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Documentation/git-ls-files.txt

@@ -44,7 +44,7 @@ OPTIONS
 
 -o::
 --others::
-	Show other files in the output
+	Show other (i.e. untracked) files in the output
 
 -i::
 --ignored::