Granular TextMate Scope for Function Parameters in GDScript

### Godot version

3.6

### VS Code version

1.121

### Godot Tools VS Code extension version

Latest

### System information

Windows 10

### Problem statement

### Summary

Currently, function parameters in GDScript do not retain a distinct TextMate scope when referenced inside the function body. This makes it impossible for color themes to visually distinguish parameters from regular local variables, limiting the expressiveness of syntax highlighting.

---

### Current Behavior

When inspecting tokens via **Developer: Inspect Editor Tokens and Scopes**, a parameter referenced inside the function body resolves only to:

```
source.gdscript
```

While the same parameter in the function **signature** resolves to:

```
variable.other.gdscript
meta.function.parameters.gdscript
meta.function-call.gdscript
source.gdscript
```

### Expected Behavior

Parameters should carry a dedicated scope such as `variable.parameter.gdscript` both at the declaration site and at every usage site within the function body. This is consistent with how other language grammars handle parameters — for example, Python and TypeScript both expose `variable.parameter` scopes inside function bodies.

### Why This Matters

Without this scope, theme authors have no way to target parameters specifically. The only workaround — targeting `variable.other.gdscript` broadly — incorrectly colorizes all variables, not just parameters, making it unusable.

This is a common request from developers who use custom or third-party color themes and want semantic visual distinction between:
- **Parameters** (passed into the function)
- **Local variables** (declared inside the function)
- **Member variables** (declared at class level)

### Environment

- Extension: `godot-tools` (geequlim.godot-tools)
- Editor: VSCodium / VS Code
- Godot version: 3.x 4.x
- OS: Windows

### Proposed solution

### Suggested Grammar Change

In the GDScript TextMate grammar, parameter tokens inside the function body should be assigned the scope:

```
variable.parameter.gdscript
```

This would allow theme authors to target them precisely:

```json
{
"scope": "variable.parameter.gdscript",
"settings": { "foreground": "#940AFF" }
}
```

Start by locating the GDScript TextMate grammar used by the Godot Tools VS Code extension, then use VS Code's Developer: Inspect Editor Tokens and Scopes on a parameter declaration and reference. The change is done when both sites expose variable.parameter.gdscript without broadly changing local or member variable scopes.

Written by the indexing model from the issue text.