Add transitive FrameworkReference guidance to NU1510 docs

[Copilot]

NU1510 documentation did not cover the case where pruning depends on a framework reference that arrives through a project reference. This left a gap for consumers who need to add the framework reference directly before NuGet can recognize an otherwise unnecessary package reference.

• Problem clarification

  • Add a transitive-project scenario showing a library that references Microsoft.AspNetCore.App and a consumer that references the library.
  • Explain that the consumer's restore graph does not treat the transitive FrameworkReference as sufficient for pruning guidance.

• Guidance added

  • Document that the consumer might need to declare the same FrameworkReference directly.
  • Tie that step to the expected NU1510 outcome for the now-unnecessary direct PackageReference.

• NU1510 example expansion

  • Add a new example to NU1510.md with Library.csproj and Consumer.csproj.
  • Update the solution section to call out the direct FrameworkReference requirement in this scenario.

<ItemGroup>
  <ProjectReference Include="..\Library\Library.csproj" />
  <FrameworkReference Include="Microsoft.AspNetCore.App" />
  <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="8.0.0" />
</ItemGroup>

[learn-build-service-prod]

Learn Build status updates of commit 1e70f84:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/reference/errors-and-warnings/NU1510.md	✅Succeeded	View

For more details, please refer to the build report.

[learn-build-service-prod]

PoliCheck Scan Report

The following report lists PoliCheck issues in PR files. Before you merge the PR, you must fix all severity-1 and severity-2 issues. The AI Review Details column lists suggestions for either removing or replacing the terms. If you find a false positive result, mention it in a PR comment and include this text: #policheck-false-positive. This feedback helps reduce false positives in future scans.

✅ No issues found

More information about PoliCheck

Information: PoliCheck | Severity Guidance | Term
For any questions: Try searching the learn.microsoft.com contributor guides or post your question in the Learn support channel.

[learn-build-service-prod]

Learn Build status updates of commit 93775ad:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/reference/errors-and-warnings/NU1510.md	✅Succeeded	View

For more details, please refer to the build report.

[learn-build-service-prod]

PoliCheck Scan Report

The following report lists PoliCheck issues in PR files. Before you merge the PR, you must fix all severity-1 and severity-2 issues. The AI Review Details column lists suggestions for either removing or replacing the terms. If you find a false positive result, mention it in a PR comment and include this text: #policheck-false-positive. This feedback helps reduce false positives in future scans.

✅ No issues found

More information about PoliCheck

Information: PoliCheck | Severity Guidance | Term
For any questions: Try searching the learn.microsoft.com contributor guides or post your question in the Learn support channel.

[learn-build-service-prod]

PoliCheck Scan Report

The following report lists PoliCheck issues in PR files. Before you merge the PR, you must fix all severity-1 and severity-2 issues. The AI Review Details column lists suggestions for either removing or replacing the terms. If you find a false positive result, mention it in a PR comment and include this text: #policheck-false-positive. This feedback helps reduce false positives in future scans.

✅ No issues found

More information about PoliCheck

Information: PoliCheck | Severity Guidance | Term
For any questions: Try searching the learn.microsoft.com contributor guides or post your question in the Learn support channel.

[learn-build-service-prod]

Learn Build status updates of commit 42c65bf:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/reference/errors-and-warnings/NU1510.md	✅Succeeded	View

For more details, please refer to the build report.

[Copilot]

Pull request overview

This PR updates the NU1510 warning documentation to cover a transitive FrameworkReference scenario where pruning guidance requires the consumer project to declare the framework reference directly.

Changes:

• Adds ai-usage metadata and updates the document date.
• Renames the original content to Scenario 1.
• Adds Scenario 2 with Library.csproj and Consumer.csproj examples for direct FrameworkReference guidance.