Lint the repo, not the docsite.

This is a fix from a misunderstanding I had. I thought antsibull-docs
lints the docsite, but it actually lints the contents of the
documentation fragments and argumnent specs.

.github/workflows/lint-docs.yaml

@@ -20,13 +20,8 @@ jobs:
     runs-on: ubuntu-latest
     permissions:
       contents: read
-    needs:
-      - build-docs
     steps:
-      - uses: actions/download-artifact@v4
-        with:
-          name: ${{ needs.build-docs.outputs.artifact-name }}
-          github_token: ${{ secrets.GITHUB_TOKEN }}
+      - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
         with:
           python-version: '3.11'