Add missing NegotiateStream API documentation

[aik-jahoda]

Summary

Add missing NegotiateStream API documentation.

part of: dotnet/runtime#41446

[opbld30]

Docs Build status updates of commit 21f691e:

⚠️ Validation status: warnings

File	Status	Preview URL	Details
xml/System.Net.Security/NegotiateStream.xml	⚠️Warning	View	Details

xml/System.Net.Security/NegotiateStream.xml

• Line 0, Column 0: [Warning-xref-not-found] Cross reference not found: 'System.IO.Stream.System#IDisposable#Dispose'.

For more details, please refer to the build report.

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[aik-jahoda]

I don't know what causes the invalid xref so I created an issue: #4763

[carlossanlop]

The CI warning is weird. Closing and reopening to retrigger.

[opbld30]

Docs Build status updates of commit 21f691e:

🕙 Pending: waiting for processors (14 builds ahead of you)

⚠️ Docs Build is busy, currently there are 14 builds ahead of this one, for more information you can view the Build queue graph on the Docs Portal.

[opbld34]

Docs Build status updates of commit 21f691e:

⚠️ Validation status: warnings

File	Status	Preview URL	Details
xml/System.Net.Security/NegotiateStream.xml	⚠️Warning	View	Details

xml/System.Net.Security/NegotiateStream.xml

• Line 0, Column 0: [Warning-xref-not-found] Cross reference not found: 'System.IO.Stream.System#IDisposable#Dispose'.

For more details, please refer to the build report.

If you see build warnings/errors with permission issues, it might be due to single sign-on (SSO) enabled on Microsoft's GitHub organizations. Please follow instructions here to re-authorize your GitHub account to Docs Build.

Note: Broken links written as relative paths are included in the above build report. For broken links written as absolute paths or external URLs, see the broken link report.

Note: Your PR may contain errors or warnings unrelated to the files you changed. This happens when external dependencies like GitHub alias, Microsoft alias, cross repo links are updated. Please use these instructions to resolve them.

For any questions, please:

• Try searching in the Docs contributor and Admin Guide
• See the frequently asked questions
• Post your question in the Docs support channel