Add distinct search parameter

[Ja7ad]

Pull Request

Related issue

Fixes #542

What does this PR do?

• This PR accept distinct search parameter, Refer to docs for more information.

PR checklist

Please check if your PR fulfills the following requirements:

• [x] Does this PR fix an existing issue, or have you listed the changes applied in the PR description (and why they are needed)?
• [x] Have you read the contributing guidelines?
• [x] Have you made sure that the title is accurate and descriptive of the changes?

Thank you so much for contributing to Meilisearch!

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 86.80%. Comparing base (59cdcef) to head (3459ce4). Report is 3 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #548 +/- ## ========================================== + Coverage 86.78% 86.80% +0.01% ========================================== Files 11 11 Lines 1635 1637 +2 ========================================== + Hits 1419 1421 +2 Misses 117 117 Partials 99 99 ```

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[meili-bors[bot]]

Build succeeded:

• integration-tests (go current version)
• integration-tests (go latest version)
• linter