Add semantic-highlighter system-generated processor documentation

[junqiu-lei]

Description

Adds documentation for the semantic-highlighter system-generated processor to address missing processor in the system-generated search processors documentation.

Issues Resolved

Addresses comment https://github.com/opensearch-project/documentation-website/pull/11024/files#r2411788264

Version

3.3+

Frontend features

N/A

If you're submitting documentation for an OpenSearch Dashboards feature, add a video that shows how a user will interact with the UI step by step. A voiceover is optional.

Checklist

• By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and subject to the Developers Certificate of Origin.
  For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[github-actions]

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[kolchfa-aws]

Hey @junqiu-lei, let me know when this PR is ready for doc review. We have 3 days left before the release.

[bzhangam]

Looks good to me.

[junqiu-lei]

Hey @junqiu-lei, let me know when this PR is ready for doc review. We have 3 days left before the release.

Hi @kolchfa-aws , the PR is ready for doc team to review, thanks!

[kolchfa-aws]

Thanks, @junqiu-lei!