refs and cleanup

Author: SimonCropp

src/Directory.Packages.props

@@ -4,12 +4,12 @@
     <CentralPackageTransitivePinningEnabled>true</CentralPackageTransitivePinningEnabled>
   </PropertyGroup>
   <ItemGroup>
-    <PackageVersion Include="MarkdownSnippets.MsBuild" Version="28.0.0-beta.11" />
+    <PackageVersion Include="MarkdownSnippets.MsBuild" Version="28.0.0-beta.24" />
     <PackageVersion Include="Magick.NET-Q16-AnyCPU" Version="14.10.2" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
     <PackageVersion Include="NUnit" Version="4.4.0" />
     <PackageVersion Include="NUnit3TestAdapter" Version="5.2.0" Pinned="true" />
-    <PackageVersion Include="Polyfill" Version="9.7.3" />
+    <PackageVersion Include="Polyfill" Version="9.7.6" />
     <PackageVersion Include="ProjectDefaults" Version="1.0.170" />
     <PackageVersion Include="Verify" Version="31.9.4" />
     <PackageVersion Include="Verify.DiffPlex" Version="3.1.2" />