No syntax highlight in workflow files

**Describe the bug**
I have the following VS Code configuration:

```json
"[github-actions-workflow]": {
"editor.defaultFormatter": "github.vscode-github-actions",
"editor.formatOnSave": true,
"editor.tabSize": 2,
},
```

Yet, when trying to modify `.github/workflows/test.yml`, I get no syntax highlight for the file, despite being correctly recognized as a `Github Actions Workflow`.


**To Reproduce**
Steps to reproduce the behavior:
1. With this workflow '...'
2. Do this '...'
3. See error

**Expected behavior**
A clear and concise description of what you expected to happen.

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Extension Version**
`v1.x.y`

**Additional context**
Add any other context about the problem here.

Reproduce the issue with the provided VS Code language configuration and a representative .github/workflows/test.yml file. No source file, test, or entry point is named in the report, so first locate the extension's workflow-language and syntax-highlighting setup; done means workflow files receive syntax highlighting while retaining their GitHub Actions language mode.

Rédigé par le modèle d'indexation à partir du texte de l'issue.