Include a warning about host spoofing in xml

[divyeshio]

Include a warning about host spoofing in xml

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Summary of the changes

Adds remarks for warning about host spoofing
Changes taken from previously unmerged PR #54971

Description

Update API remarks for RoutingEndpointConventionBuilderExtensions.RequireHost to warn about host spoofing

This is how it looks like in VS code after changes. Idk why crefs are not rendered properly in VS code.

Fixes #48818

[dotnet-policy-service]

Thanks for your PR, @@divyeshio. Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[Copilot]

Pull Request Overview

This PR adds important security-related documentation to the RequireHost method by including XML documentation remarks that warn developers about host spoofing vulnerabilities. The changes provide guidance on how to properly verify server names and local ports to prevent spoofing attacks.

• Adds comprehensive XML documentation with security warnings about Host header spoofing
• Provides specific mitigation recommendations using TLS handshake verification and connection info validation
• Includes a new using directive for Microsoft.AspNetCore.Http to support the documentation references