refs and cleanup

Author: SimonCropp

src/Directory.Packages.props

@@ -5,17 +5,17 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageVersion Include="FluentValidation" Version="12.1.1" />
-    <PackageVersion Include="MarkdownSnippets.MsBuild" Version="28.0.0" />
+    <PackageVersion Include="MarkdownSnippets.MsBuild" Version="28.0.1" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.3.0" />
     <PackageVersion Include="Microsoft.Sbom.Targets" Version="4.1.5" />
     <PackageVersion Include="NUnit" Version="4.5.0" />
     <PackageVersion Include="NUnit3TestAdapter" Version="6.1.0" />
     <PackageVersion Include="ProjectDefaults" Version="1.0.172" />
-    <PackageVersion Include="Polyfill" Version="9.17.0" />
+    <PackageVersion Include="Polyfill" Version="9.18.0" />
     <PackageVersion Include="Verify.DiffPlex" Version="3.1.2" />
     <PackageVersion Include="Verify.NUnit" Version="31.13.2" />
     <PackageVersion Include="Argon" Version="0.33.5" />
-    <PackageVersion Include="DiffEngine" Version="18.4.2" />
+    <PackageVersion Include="DiffEngine" Version="19.0.0" />
     <PackageVersion Include="EmptyFiles" Version="8.17.2" />
     <PackageVersion Include="SimpleInfoName" Version="3.2.0" />
     <PackageVersion Include="Verify" Version="31.13.2" />