Preserve literal carriage returns with dos2unix

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

.github/workflows/gitignore-formatting.yml

@@ -27,6 +27,11 @@ jobs:
       - name: Install formatting tools
         run: python -m pip install pre-commit-hooks==6.0.0
 
+      - name: Install dos2unix
+        run: |
+          sudo apt-get update
+          sudo apt-get install --yes dos2unix
+
       - name: Check all gitignore files recursively
         shell: bash
         run: |
@@ -41,13 +46,14 @@ jobs:
           echo "Checking ${#files[@]} gitignore files."
 
           status=0
-          mixed-line-ending --fix=lf -- "${files[@]}" || status=1
+          dos2unix --keep-bom -- "${files[@]}" || status=1
           trailing-whitespace-fixer -- "${files[@]}" || status=1
           end-of-file-fixer -- "${files[@]}" || status=1
 
+          git --no-pager diff --no-ext-diff --exit-code -- "${files[@]}" || status=1
+
           if (( status != 0 )); then
-            echo "::error::Formatting checks failed. See tool output and diff below."
-            git --no-pager diff --no-ext-diff -- "${files[@]}"
+            echo "::error::Formatting checks failed. See tool output and diff above."
           fi
 
           exit "$status"