docs: Remove 'proper shutdown' from TODO list

hey, i know this is ugly
but it works!

README.md

@@ -8,4 +8,3 @@ Drop-in replacement for busybox init (kind of)
 
 - askfirst handling
 - other devices than /dev/console
-- proper shutdown

main.go

@@ -57,6 +57,12 @@ func main() {
 
 	signal.Notify(sigs, syscall.SIGUSR2, syscall.SIGTERM, syscall.SIGQUIT, syscall.SIGINT)
 
+	go func() {
+		for {
+			syscall.Wait4(-1, nil, 0, nil)
+		}
+	}()
+
 	select {}
 }
 

process.go

@@ -30,10 +30,8 @@ func Exec(entry InitTabEntry) error {
 		return fmt.Errorf("spawn: %w", err)
 	}
 
-	err = cmd.Wait()
-	if err != nil {
-		return fmt.Errorf("wait: %w", err)
-	}
+	// skipping error handling due to wait4 in main
+	cmd.Wait()
 
 	return nil
 }