Bump MarkdownSnippets.MsBuild from 28.3.1 to 28.4.0

---
updated-dependencies:
- dependency-name: MarkdownSnippets.MsBuild
  dependency-version: 28.4.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

src/Directory.Packages.props

@@ -5,7 +5,7 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageVersion Include="Argon.Xml" Version="0.34.0" />
-    <PackageVersion Include="MarkdownSnippets.MsBuild" Version="28.3.1" />
+    <PackageVersion Include="MarkdownSnippets.MsBuild" Version="28.4.0" />
     <PackageVersion Include="Microsoft.Extensions.DiagnosticAdapter" Version="3.1.32" />
     <PackageVersion Include="Microsoft.Extensions.Http" Version="10.0.9" />
     <PackageVersion Include="Microsoft.Net.Http.Headers" Version="10.0.9" />