[BUG] Completion doesn't override parentheses

Extension: 0.1.6
LLM LS: 0.4.0

Usually when you declare a function or other variables, the editor adds a closing bracket.

For example:

```python
def foo()
```

When you type `(`, the editor adds `)` automatically. After accepting the completion, the output looks something like:

```python
def foo(bar: str):)
```

Maybe we should use the bracket as a stop token, but that would mean the completion would be one line only for these cases.

Note: I'm using a local model