refs and cleanup

Author: SimonCropp

src/Directory.Packages.props

@@ -6,8 +6,8 @@
   <ItemGroup>
     <PackageVersion Include="MarkdownSnippets.MsBuild" Version="28.0.0-beta.10" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
-    <PackageVersion Include="Polyfill" Version="9.3.4" />
-    <PackageVersion Include="ProjectDefaults" Version="1.0.166" />
+    <PackageVersion Include="Polyfill" Version="9.4.1" />
+    <PackageVersion Include="ProjectDefaults" Version="1.0.167" />
     <PackageVersion Include="TestableIO.System.IO.Abstractions" Version="22.1.0" />
     <PackageVersion Include="TestableIO.System.IO.Abstractions.Wrappers" Version="22.1.0" />
     <PackageVersion Include="Verify" Version="31.9.0" />