Update What's New documentation for .NET 10 RC 2

[Copilot]

This PR updates the .NET 10 What's New documentation to reflect the RC 2 release, following the guidelines in .github/prompts/whats-new-net.md.

Changes

Updated all four What's New articles for .NET 10 RC 2:

• overview.md: Updated to reflect RC 2 as the latest release
• runtime.md: Updated for RC 2 (focused on quality improvements as the release approaches GA)
• libraries.md: Updated for RC 2 (focused on quality improvements as the release approaches GA)
• sdk.md: Updated for RC 2 and added comprehensive documentation for the new "Use .NET MSBuild Tasks with .NET Framework MSBuild" feature

New Feature: .NET MSBuild Tasks with .NET Framework MSBuild

The most significant addition in RC 2 is support for running .NET MSBuild tasks in Visual Studio 2026 and msbuild.exe. Previously, MSBuild running in Visual Studio (a .NET Framework application) could only execute .NET Framework tasks, while MSBuild in the dotnet CLI (a .NET application) could run .NET tasks.

Starting with .NET 10, task authors can write MSBuild tasks that target .NET and have them work everywhere, including Visual Studio and msbuild.exe. The documentation includes:

• Overview of the feature and its benefits for task authors
• Configuration examples showing how to opt-in using Runtime="NET" and TaskFactory="TaskHostFactory"
• Performance tuning guidance for optimizing in-process vs. out-of-process execution
• Known limitations and caveats
• Future roadmap for additional capabilities

Metadata Updates

All files now have:

• ms.date updated to 10/15/2025
• Introduction text updated to reference "RC 2"
• Verified ai-usage: ai-assisted metadata present

Source Material

Content based on official .NET 10 RC 2 release notes from the dotnet/core repository, adapted per Microsoft Writing Style Guide (removed first-person references and marketing language, converted to second person).

Fixes #<issue_number>

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Generate What's new for .NET 10 RC 2</issue_title>
<issue_description>### Describe the issue or suggestion

Create the update for .NET 10 RC 2 using the instructions found here: https://github.com/dotnet/docs/blob/main/.github/prompts/whats-new-net.md

This is a release candidate preview release, so the folder named as "preview" in the prompt is "rc2".

</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #49282

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Internal previews

📄 File	🔗 Preview link
docs/core/whats-new/dotnet-10/libraries.md	What's new in .NET libraries for .NET 10
docs/core/whats-new/dotnet-10/overview.md	What's new in .NET 10
docs/core/whats-new/dotnet-10/runtime.md	What's new in .NET 10 runtime
docs/core/whats-new/dotnet-10/sdk.md	What's new in the SDK and tooling for .NET 10

[BillWagner]

This LGTM. Tagging others for final review.

[Copilot]

Pull Request Overview

Updates What's New documentation for .NET 10 RC 2, adding the new MSBuild tasks interoperability feature and updating metadata/version references from RC 1 to RC 2.

• Updated ms.date and RC version text across overview, runtime, libraries, and SDK articles
• Added new section detailing how to use .NET MSBuild tasks with .NET Framework MSBuild (Visual Studio / msbuild.exe)
• Included configuration, performance notes, limitations, and future roadmap for the MSBuild task hosting feature

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
docs/core/whats-new/dotnet-10/overview.md	Updated ms.date and RC version reference text
docs/core/whats-new/dotnet-10/runtime.md	Updated ms.date and RC version reference text
docs/core/whats-new/dotnet-10/libraries.md	Updated ms.date and RC version reference text
docs/core/whats-new/dotnet-10/sdk.md	Added new MSBuild tasks interoperability section and updated ms.date / RC reference

[meaghanlewis]

This LGTM @BillWagner. Just a handful of suggestions to consider.