Add Windows 10 version numbers (1903–21H2) to .NET Framework versions-and-dependencies page

[Copilot]

Windows 10 update entries in the .NET Framework versions table were missing their numeric version identifiers, making it hard to correlate OS releases with .NET Framework support.

Changes

• .NET Framework 4.8 table — added version labels to all previously unlabeled Windows 10 entries:

  • May 2019 Update → (Version 1903)
  • November 2019 Update → (Version 1909)
  • May 2020 Update → (Version 2004)
  • October 2020 Update → (Version 20H2)
  • May 2021 Update → (Version 21H1)
  • November 2021 Update → (Version 21H2)

• .NET Framework 4.8.1 table — same treatment for the three entries that overlapped (20H2, 21H1, 21H2), matching the style already used for older entries like (Version 1809).

Original prompt

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This section details on the original issue you should resolve

<issue_title>Windows 10 versions 1909 and 2004 not listed</issue_title>
<issue_description>The last two releases of Windows 10 (1909 and 2004) are not listed on the page. Please update the page to account for these with their respective .NET versions.

In addition, it would be helpful if the "10 May 2019 Update" was also referred to as 1903 for clarity, just as other versions are on the page.

Thanks.

[Edited below to add doc details.]

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Document Details

⚠ Do not edit this section. It is required for docs.microsoft.com ➟ GitHub issue linking.

• ID: 81fe5242-e3b2-6cfe-5308-63fc96272657
• Version Independent ID: 1abaaeb7-d7ed-5522-c16f-409f22a074cc
• Content: .NET Framework & Windows OS versions
• Content Source: docs/framework/migration-guide/versions-and-dependencies.md
• Product: dotnet-framework
• Technology: dotnet-appcompat
• GitHub Login: @gewarren
• Microsoft Alias: gewarren</issue_description>

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

• Fixes Windows 10 versions 1909 and 2004 not listed #21099

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