Solution Explorer search is not showing package contents

[drewnoakes]

Repro steps

1. Add a NuGet package to a project
2. Expand it to find some inner content, such as a transitively referenced project
3. Enable "Search external items" in the Solution Explorer search box dropdown
4. Search for package content
5. Notice it is not displayed

For example, Shouldly version 4.0.3 shows this tree, where the highlighted region is considered "inner content":

Configure search:

Search for DiffEngine:

Search results should not be empty.

The search provider lives in the NuGet.Client repo, but we maintain that code so I am tracking the work item here.

https://github.com/NuGet/NuGet.Client/blob/dev/src/NuGet.Clients/NuGet.VisualStudio.Implementation/SolutionExplorer/AssetsFileDependenciesTreeSearchProvider.cs