Bump DocFx.App from 2.77.0 to 2.78.2

Bumps [DocFx.App](https://github.com/dotnet/docfx) from 2.77.0 to 2.78.2.
- [Release notes](https://github.com/dotnet/docfx/releases)
- [Changelog](https://github.com/dotnet/docfx/blob/main/RELEASENOTE.md)
- [Commits](dotnet/docfx@v2.77.0...2.78.2)

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

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

Directory.Packages.props

@@ -7,7 +7,7 @@
 	<PackageVersion Include="CommunityToolkit.Diagnostics" Version="8.3.0" />
 	<PackageVersion Include="coverlet.collector" Version="6.0.2" />
 	<PackageVersion Include="coverlet.msbuild" Version="6.0.2" />
-	<PackageVersion Include="DocFx.App" Version="2.77.0" />
+	<PackageVersion Include="DocFx.App" Version="2.78.2" />
 	<PackageVersion Include="GitHubActionsTestLogger" Version="2.4.1" />
 	<PackageVersion Include="Microsoft.Bcl.HashCode" Version="1.1.1" />
 	<PackageVersion Include="Microsoft.CodeAnalysis.Analyzers" Version="3.11.0" />