unpack-trees: fix grammar for untracked files in directories

Noticed-by: David Turner <dturner@twosigma.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Reviewed-by: David Turner <dturner@twosigma.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t7609-merge-co-error-msgs.sh

diff --git a/t/t7609-merge-co-error-msgs.sh b/t/t7609-merge-co-error-msgs.sh
index 6729cb3..85cd971 100755
--- a/t/t7609-merge-co-error-msgs.sh
+++ b/t/t7609-merge-co-error-msgs.sh
@@ -105,7 +105,7 @@
 '
 
 cat >expect <<\EOF
-error: Updating the following directories would lose untracked files in it:
+error: Updating the following directories would lose untracked files in them:
 	rep
 	rep2
 

unpack-trees.c

diff --git a/unpack-trees.c b/unpack-trees.c
index aea9aa7..129a354 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -78,7 +78,7 @@
 		xstrfmt(msg, cmd, cmd);
 
 	msgs[ERROR_NOT_UPTODATE_DIR] =
-		_("Updating the following directories would lose untracked files in it:\n%s");
+		_("Updating the following directories would lose untracked files in them:\n%s");
 
 	if (!strcmp(cmd, "checkout"))
 		msg = advice_commit_before_merge