Allow Refactoring inner GDScript assets.

### Godot version

4.4.1

### VS Code version

1.100.0

### Godot Tools VS Code extension version

2.5.1

### System information

Win10

### Problem statement

My workflow for Godot has generally been most scripts go into the scene itself. I only break assets/scripts/scenes off into separate files when they reach a certain complexity. As such: refactoring tools are amazing, BUT they don't reach inner script assets inside scenes.

### Proposed solution

Also parse `[sub_resource type="GDScript"]` inner assets and refactor them along with other scripts.