💡 Trellias alias should add snippet to site/wp-cli.yml or an alternative wp-cli.yml (or wp-cli.local.yml) config.

### Summary

it would be nice if the alias command automaticly added the 

```yml
_:
  inherit: wp-cli.trellis-alias.yml
```

snippet to site/wp-cli.yml or an alternative wp-cli.yml (or wp-cli.local.yml) config. ❤️ 

AC:

alias command

* should add snippet to config file
* should not add if snippet exists



### Additional context

_No response_