build(deps): bump Markdig from 0.38.0 to 0.40.0 (dotnet#10499)

Bumps [Markdig](https://github.com/xoofx/markdig) from 0.38.0 to 0.40.0.
- [Release notes](https://github.com/xoofx/markdig/releases)
- [Changelog](https://github.com/xoofx/markdig/blob/master/changelog.md)
- [Commits](xoofx/markdig@0.38.0...0.40.0)

---
updated-dependencies:
- dependency-name: Markdig
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Directory.Packages.props

@@ -8,7 +8,7 @@
     <PackageVersion Include="ICSharpCode.Decompiler" Version="9.0.0.7889" />
     <PackageVersion Include="Jint" Version="4.1.0" />
     <PackageVersion Include="JsonSchema.Net" Version="7.2.3" />
-    <PackageVersion Include="Markdig" Version="0.38.0" />
+    <PackageVersion Include="Markdig" Version="0.40.0" />
     <PackageVersion Include="Microsoft.Playwright" Version="1.49.0" />
     <PackageVersion Include="Newtonsoft.Json" Version="13.0.3" />
     <PackageVersion Include="OneOf" Version="3.0.271" />