[DOC]Enhance Logstash geo_shape field example

[tatecn]

What do you want to do?

• Request a change to existing documentation
• Add new documentation
• Report a technical problem with the documentation
• Other

Tell us about your request. Provide a summary of the request.
I encountered an issue while using the logstash-output-opensearch plugin to process the geo_shape field.
It seems there are no examples or clear solutions addressing this problem.
Perhaps we could improve the documentation or provide an example to help clarify this.

I hope I could help improve.
Version: List the OpenSearch version to which this issue applies, e.g. 2.14, 2.12--2.14, or all.
2.11 or above, I use 2.11

What other resources are available? Provide links to related issues, POCs, steps for testing, etc.
Relevant issue: Can't index document for geo_shape field using logstash jdbc input