Add suggestions menu when using "_source" completion in query

### Is your feature request related to a problem?

I often disable "_source" in queries, but when choosing completion it adds
```
"_source": {
    "includes": [
      ""
    ]
  }
```


### Describe the solution you'd like

I would like to be able to choose which kind I want to enter - `includes` or `false`

### Additional context

_No response_