Update search.md

[romaincomeau]

Getting an error when omitting the body parameter using the client's index method as per guide/search.md
Client version

romaincomeau@phoenix tests % npm list | grep opensearch
├── @opensearch-project/opensearch@2.13.0
romaincomeau@phoenix tests %

Server versions

admin@opensearch-oh-a:~ $ pkg version | grep opensearch
opensearch-2.14.0                  =
opensearch-dashboards-2.14.0       =
admin@opensearch-oh-a:~ $ uname -a
FreeBSD opensearch-oh-a 14.1-RELEASE-p5 FreeBSD 14.1-RELEASE-p5 GENERIC amd64
admin@opensearch-oh-a:~ $

ConfigurationError: Missing required parameter: body

  114 |         })
  115 |
> 116 |         await ds.client.index({ index: "movies", refresh: true })
      |                         ^
  117 |       })
  118 |       afterAll(async () => {
  119 |         await ds.client.indices.delete({ index: "movies" })

  at Client.indexApi [as index] (node_modules/@opensearch-project/opensearch/api/api/index.js:103:17)
  at Object.index (classes/tests/app_datasource_opensearch.e2e.test.js:116:25)

Description

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Issues Resolved

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Check List

• New functionality includes testing.
  • All tests pass
• Linter check was successfull - yarn run lint doesn't show any errors
• Commits are signed per the DCO using --signoff
• Changelog was updated.

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