Unable to find reusable workflow

**Describe the bug**
When leveraging local reusable workflows, i.e. referencing other workflows inside of the `.github/workflows/` directory, the extension claims that it cannot find the reusable workflow. The reusable workflow is indeed in the right place, and it executes successfully by Github Actions.

**To Reproduce**
Steps to reproduce the behavior:
1. With the following directory structure:
```dir
.github/workflows/
- base.yml
- reusable.yml
```
And the following workflows:
```yml
# base.yml
name: base
on:
pull_request:

permissions:
contents: read
id-token: write

jobs:
reusable:
uses: ./.github/workflows/reusable.yml
with:
EXAMPEL: example
```
```yml
# reusable.yml
name: reusable
on:
workflow_call:
inputs:
EXAMPLE:
description: Example.
type: string
required: true

permissions:
contents: read
id-token: write

jobs:
reusable:
name: Example
runs-on: ubuntu-latest
steps:
- name: Example step
run: echo "${{ inputs.EXAMPLE }}"
```
2. Go to `base.yml` in VS Code.
3. The linting error `Unable to find reusable workflow` is presented. In addition, this is the output from `Github Actions Language`:
```
[Error - 09:26:39] Request textDocument/documentLink failed.
Message: Request textDocument/documentLink failed with message: Invalid file reference: .github/workflows/reusable.yml
Code: -32603
```

**Expected behavior**
As this is indeed a valid file reference according to [github documentation](https://docs.github.com/en/actions/using-workflows/reusing-workflows#calling-a-reusable-workflow), and since it does indeed execute successfully, this error should not occur.

**Screenshots**

**Extension Version**
`v0.26.1`

Reproduce the failure in VS Code using base.yml and .github/workflows/reusable.yml, then inspect the documentLink request and the reusable-workflow reference handling. Confirm that the local path is accepted, the linting error disappears, and the document link resolves without an Invalid file reference error.

由索引模型根据 Issue 内容生成。