gui: fix screenshot_saved message

Change-Id: I7d047fe3436100dbe7c7515860a143a97f7ef0d4
diff --git a/gui/action.cpp b/gui/action.cpp
index 081e2d1..9f746c3 100644
--- a/gui/action.cpp
+++ b/gui/action.cpp
@@ -928,7 +928,7 @@
 		chmod(path, 0666);
 		chown(path, uid, gid);
 
-		gui_msg(Msg("screenshot_saved=Screenshot was saved to %s")(path));
+		gui_msg(Msg("screenshot_saved=Screenshot was saved to {1}")(path));
 
 		// blink to notify that the screenshow was taken
 		gr_color(255, 255, 255, 255);