cvsimport: document -S and -L options

Signed-off-by: NMartin Langhoff <martin@catalyst.net.nz>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Documentation/git-cvsimport.txt

@@ -104,6 +104,14 @@ If you need to pass multiple options, separate them with a comma.
 -a::
 	Import all commits, including recent ones. cvsimport by default
 	skips commits that have a timestamp less than 10 minutes ago.
+
+-S <regex>::
+	Skip paths matching the regex.
+
+-L <limit>::
+	Limit the number of commits imported. Workaround for cases where
+	cvsimport leaks memory.
+
 +
 ---------
 	exon=Andreas Ericsson <ae@op5.se>