refs and cleanup

Author: SimonCropp

src/Directory.Packages.props

@@ -8,7 +8,7 @@
     <PackageVersion Include="MarkdownSnippets.MsBuild" Version="28.0.0" />
     <PackageVersion Include="Microsoft.AspNetCore.TestHost" Version="10.0.3" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.3.0" />
-    <PackageVersion Include="Polyfill" Version="9.12.0" />
+    <PackageVersion Include="Polyfill" Version="9.13.0" />
     <PackageVersion Include="ProjectDefaults" Version="1.0.172" />
     <PackageVersion Include="Verify.DiffPlex" Version="3.1.2" />
     <PackageVersion Include="Verify.XunitV3" Version="31.13.2" />