Watch new files

I'm using the following command with Riot CLI 4.0.2 to watch .riot changes in the src folder and write ES modules and maps back to the src folder. It works great except that new .riot files are not picked up. So I have to restart the command any time I add a new file.

```
npx riot -w src -o src --sourcemap file
```

My request is for riot to watch for new .riot files.