Add example for C4066

[Rageking8]

Add short example and demonstrated the behaviour mentioned:

The compiler processes only the first character of a wide-character constant.

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Learn Build status updates of commit a465ba7:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/error-messages/compiler-warnings/compiler-warning-level-3-c4066.md	✅Succeeded

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PRMerger Results

Issue	Description
File Change Percent	This PR contains file(s) with more than 30% file change.

[Jak-MS]

@TylerMSFT

• Can you review this PR?
• IMPORTANT: When this content is ready to merge, you must add #sign-off in a comment or the approval may get overlooked.

#label:"aq-pr-triaged"
@MicrosoftDocs/public-repo-pr-review-team

[TylerMSFT]

Thanks!

[TylerMSFT]

#sign-off

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@Rageking8 : Thanks for your contribution! The author(s) have been notified to review your proposed change.