Update dbcc-show-statistics-transact-sql.md

[sommarskog]

Clarified text about string index that the restriction for UTF-8 collations only apply to char and varchar. Refer to Vassilis.Papadimos@microsoft.com for verification. (I'm creating a second pull request for the same change another topic. I have not figured out how I can get to two topics in the same PR. Sorry about that.)

[prmerger-automator]

sommarskog : Thanks for your contribution! The author(s) and reviewer(s) have been notified to review your proposed change.

[prmerger-automator]

sommarskog : Thanks for your contribution! The author(s) and reviewer(s) have been notified to review your proposed change.

[learn-build-service-prod]

Learn Build status updates of commit 3a9b56a:

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[Regan Downer (v-regandowner)]

Randolph West MSFT (@rwestMSFT)

Can you review the proposed changes?

IMPORTANT: When the changes are ready for publication, adding a #sign-off comment is the best way to signal that the PR is ready for the review team to merge.

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

[learn-build-service-prod]

Learn Build status updates of commit 0c1f8ad:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/relational-databases/statistics/view-statistics-properties.md	✅Succeeded
docs/t-sql/database-console-commands/dbcc-show-statistics-transact-sql.md	✅Succeeded

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[learn-build-service-prod]

Learn Build status updates of commit 3fa0f17:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/relational-databases/statistics/view-statistics-properties.md	✅Succeeded
docs/t-sql/database-console-commands/dbcc-show-statistics-transact-sql.md	✅Succeeded

For more details, please refer to the build report.