Incorrect formatting for negative indices/keys

### Godot version

4.4.1

### VS Code version

1.102.2

### Godot Tools VS Code extension version

2.5.1 as well as Dev Build (as of 2025-07-24)

### System information

Windows 11

### Issue description

Negative indices are not formatted correctly in certain situations. For example, `x[-1]` gets formatted to `x[ - 1]`.

### Steps to reproduce

The following code

```
some_array[-1] = 0
print(some_array[-1])
```
formats to
```
some_array[-1] = 0
print(some_array[ - 1])
```