git-add--interactive.perl: add missing dot in a message

One message appears twice in the translations and the only
difference is a dot at the end.  So add this dot to make
the messages being identical.

Signed-off-by: Ralf Thielow <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: ralfth

git-add--interactive.perl

@@ -1049,7 +1049,7 @@ sub color_diff {
 marked for applying."),
 	checkout_index => N__(
 "If the patch applies cleanly, the edited hunk will immediately be
-marked for discarding"),
+marked for discarding."),
 	checkout_head => N__(
 "If the patch applies cleanly, the edited hunk will immediately be
 marked for discarding."),