Document correct NewLineChars default values

[wenz]

Summary

Document NewLineChars default values on different operating systems.

Fixes #8315

[ghost]

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Issue Details

---

Summary

Document NewLineChars default values on different operating systems.

Fixes #8315

Author:	wenz
Assignees:	-
Labels:	area-System.Xml, community-contribution
Milestone:	-

[opbld32]

Learn Build status updates of commit 1b4c34d:

✅ Validation status: passed

File	Status	Preview URL	Details
xml/System.Xml/XmlWriter.xml	✅Succeeded	View
xml/System.Xml/XmlWriterSettings.xml	✅Succeeded	View

For more details, please refer to the build report.

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.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
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[opbld31]

Learn Build status updates of commit ff12718:

✅ Validation status: passed

File	Status	Preview URL	Details
xml/System.Xml/XmlWriter.xml	✅Succeeded	View
xml/System.Xml/XmlWriterSettings.xml	✅Succeeded	View

For more details, please refer to the build report.

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.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel

[krwq]

LGTM although consider mentioning this is correlated with https://learn.microsoft.com/en-us/dotnet/api/system.environment.newline?view=net-7.0