Document Safari's lack of *.localhost domain support

[Copilot]

Safari on macOS doesn't resolve *.localhost domains to loopback like other evergreen browsers, causing connection failures for developers using this feature.

Changes

• Browser compatibility section: Added Safari limitation note specifying users must use plain localhost instead of *.localhost domains
• Metadata: Updated ms.date to 11/19/2025

The note is placed in the existing "Browser compatibility" section where developers naturally look for browser-specific limitations.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Update localhost-tld.md with note that Safari doesn't support *.localhost domains</issue_title>
<issue_description>Turns out Safari on macOS doesn't support *.localhost domain resolution like other evergreen browsers do. We should add a note to https://learn.microsoft.com/aspnet/core/test/localhost-tld to cover this.</issue_description>

<agent_instructions>Run prompts in this copilot information file on this dotnet/AspNetCore.Docs repo:
.github/copilot-issue-verification-action-plan.md</agent_instructions>

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

• Fixes Update localhost-tld.md with note that Safari doesn't support *.localhost domains #36368

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Internal previews

📄 File	🔗 Preview link
aspnetcore/test/localhost-tld.md	Support for the .localhost top-level domain

[wadepickett]

Approved.

[wadepickett]

@tdykstra, I need review for this one, thanks.

[tdykstra]

Looks good, one suggestion.