Fix link to sharing trial capacitues

[simonsabin]

Content had a { rather than a [ so link wasn't working

[prmerger-automator]

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

[learn-build-service-prod]

Learn Build status updates of commit 34a125e:

⚠️ Validation status: warnings

File	Status	Preview URL	Details
docs/get-started/fabric-trial.md	⚠️Warning		Details

docs/get-started/fabric-trial.md

• Line 67, Column 27: [Warning: bookmark-not-found - See documentation] Cannot find bookmark '#sharing-trial-capacities' in 'get-started/fabric-trial.md', did you mean '#share-trial-capacities'?

For more details, please refer to the build report.

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[learn-build-service-prod]

Learn Build status updates of commit 7986ea2:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/get-started/fabric-trial.md	✅Succeeded

For more details, please refer to the build report.

For any questions, please:

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

[v-dirichards]

@mihart

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