Add documentation for NU1016 error code (project.json deprecation)

[Copilot]

Fixes https://github.com/nuget/home/issue/14415

This PR adds missing documentation for the NU1016 error code, which is raised when NuGet encounters a deprecated project.json project during restore operations.

Changes Made

• Added docs/reference/errors-and-warnings/NU1016.md - Complete documentation for the NU1016 error following the established pattern of other error documentation
• Updated docs/reference/Errors-and-Warnings.md - Added NU1016 to the "Invalid input errors" table

[learn-build-service-prod]

Learn Build status updates of commit 40d5b6b:

✅ Validation status: passed

For more details, please refer to the build report.

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PoliCheck Scan Report

The following report lists PoliCheck issues in PR files. Before you merge the PR, you must fix all severity-1 issues. Other issues are also a high priority. 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.

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[learn-build-service-prod]

Learn Build status updates of commit 5344788:

💡 Validation status: suggestions

File	Status	Preview URL	Details
docs/reference/errors-and-warnings/NU1016.md	💡Suggestion	View	Details
docs/reference/Errors-and-Warnings.md	✅Succeeded	View

docs/reference/errors-and-warnings/NU1016.md

• Line 5, Column 12: [Suggestion: ms-author-invalid - See documentation] Invalid value for 'ms.author', 'anangaur' is not a valid Microsoft alias.

For more details, please refer to the build report.

Note: Your PR may contain errors or warnings or suggestions unrelated to the files you changed. This happens when external dependencies like GitHub alias, Microsoft alias, cross repo links are updated. Please use these instructions to resolve them.

[learn-build-service-prod]

Learn Build status updates of commit 34c1e37:

💡 Validation status: suggestions

File	Status	Preview URL	Details
docs/reference/errors-and-warnings/NU1016.md	💡Suggestion	View	Details
docs/reference/Errors-and-Warnings.md	✅Succeeded	View

docs/reference/errors-and-warnings/NU1016.md

• Line 5, Column 12: [Suggestion: ms-author-invalid - See documentation] Invalid value for 'ms.author', 'anangaur' is not a valid Microsoft alias.

For more details, please refer to the build report.

Note: Your PR may contain errors or warnings or suggestions unrelated to the files you changed. This happens when external dependencies like GitHub alias, Microsoft alias, cross repo links are updated. Please use these instructions to resolve them.

[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 issues. Other issues are also a high priority. 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 issues. Other issues are also a high priority. 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 4cca413:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/reference/Errors-and-Warnings.md	✅Succeeded	View
docs/reference/errors-and-warnings/NU1016.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 issues. Other issues are also a high priority. 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.

[Copilot]

Pull Request Overview

This PR adds comprehensive documentation for the NU1016 error code, which is raised when NuGet encounters deprecated project.json projects during restore operations. The error indicates that projects using the deprecated project.json format need to be migrated to the newer PackageReference format.

• Added complete documentation for NU1016 error following established documentation patterns
• Updated the errors and warnings index to include the new NU1016 entry
• Provided migration guidance with step-by-step instructions for different Visual Studio versions

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
docs/reference/errors-and-warnings/NU1016.md	New documentation page explaining NU1016 error with migration guidance
docs/reference/Errors-and-Warnings.md	Added NU1016 link to the "Invalid input errors" table

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[learn-build-service-prod]

Learn Build status updates of commit e4d2270:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/reference/Errors-and-Warnings.md	✅Succeeded	View
docs/reference/errors-and-warnings/NU1016.md	✅Succeeded	View

For more details, please refer to the build report.