Restructure deprecation notice to lead with key information (#49677)

* Initial plan

* Restructure deprecation notice to lead with key information

Co-authored-by: adegeo <67293991+adegeo@users.noreply.github.com>

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: adegeo <67293991+adegeo@users.noreply.github.com>

Author: Copilot

docs/core/porting/includes/github-copilot-suggestion.md

@@ -6,4 +6,4 @@ ms.topic: include
 ---
 
 > [!IMPORTANT]
-> .NET Upgrade Assistant is officially deprecated and has been replaced by [GitHub Copilot app modernization chat agent](../github-copilot-app-modernization/overview.md), which is included with Visual Studio 2026 and Visual Studio 2022 17.14.16 or later. This agent analyzes your projects and dependencies, produces a step-by-step migration plan with targeted recommendations and automated code fixes, and commits each change so you can validate or roll back. It automates common porting tasks—updating project files, replacing deprecated APIs, and resolving build issues—so you can modernize faster with less manual effort.
+> .NET Upgrade Assistant is officially deprecated. Use the [GitHub Copilot app modernization chat agent](../github-copilot-app-modernization/overview.md) instead, which is included with Visual Studio 2026 and Visual Studio 2022 17.14.16 or later. This agent analyzes your projects and dependencies, produces a step-by-step migration plan with targeted recommendations and automated code fixes, and commits each change so you can validate or roll back. It automates common porting tasks—updating project files, replacing deprecated APIs, and resolving build issues—so you can modernize faster with less manual effort.