systemctl: grey out tasks limit the same way we grey out the fd store limit in the output

"systemctl status systemd-logind" otherwise looks a bit weird, since the
tasks and the fdstore lines are so close to each other but formatted
quite differently when it comes to coloring.

(cherry picked from commit 54646b1ca95373dfa3ebe5d6e7e27deeed9e77b0)

src/systemctl/systemctl-show.c

@@ -700,7 +700,7 @@ static void print_status_info(
                 printf("      Tasks: %" PRIu64, i->tasks_current);
 
                 if (i->tasks_max != UINT64_MAX)
-                        printf(" (limit: %" PRIu64 ")\n", i->tasks_max);
+                        printf("%s (limit: %" PRIu64 ")%s\n", ansi_grey(), i->tasks_max, ansi_normal());
                 else
                         printf("\n");
         }