Workflows: Check for byte order mark

.gitea/workflows/test.yaml

@@ -2,7 +2,7 @@ name: Test
 on:
   push:
     branches: ["**"]
-    paths: ["Elwig/**", "Tests/**", "Installer/Files/*.exe"]
+    paths: ["Elwig/**", "Tests/**", "Installer/Files/*.exe", ".gitea/workflows/test.yaml"]
 jobs:
   test:
     name: Run tests
@@ -10,6 +10,19 @@ jobs:
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
+      - name: Check for Byte order marks
+        shell: powershell
+        run: |
+          $pattern = [char]::ConvertFromUtf32(0xFEFF)
+          $files = git grep -IEl "^$pattern"
+          if ( $lastexitcode -ne 1 ) {
+            echo "Files with BOM found:"
+            echo $files
+            exit 1
+          } else {
+            echo "No files with BOM found"
+            exit 0
+          }
       - name: Setup MSBuild
         uses: microsoft/setup-msbuild@v1.1
       - name: Setup NuGet