docs: added YAML example to OpenAIGenerator

[ritikraj2425]

Related Issues:
fixes #11134

Proposed Changes:

• Fixed a missing closing parenthesis syntax error in the OpenAIGenerator Python code example at line 125.
• Added a YAML representation of the RAG pipeline to the OpenAIGenerator documentation.
• Included an introductory sentence explaining how the pipeline retrieves documents, templates the prompt, and generates an answer.

How did you test it?

• Manual verification: Read through the YAML representation, validating that the connection mappings accurately match the Python code block.
• Tested the syntax fix for pipe.add_component("llm", OpenAIGenerator(...)) to ensure correct Python evaluation.

Notes for the reviewer
The YAML example was placed at the end of the ### In a Pipeline section. A small Python typo in the docs was also fixed.

Checklist

• I have read the contributors guidelines...
• I have updated the related issue...
• I have added unit tests and updated the docstrings. (N/A for documentation changes)
• I've used one of the conventional commit types... docs:
• I have documented my code.
• I have added a release note file.
• I have run pre-commit hooks and fixed any issue.

[vercel]

@ritikraj2425 is attempting to deploy a commit to the deepset Team on Vercel.

A member of the Team first needs to authorize it.

[anakin87]

Thank you!

I found some aspects to improve

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
haystack-docs	Ready	Preview, Comment	Apr 20, 2026 7:41am

[ritikraj2425]

Hey @anakin87,
All the comments are resolved!

[anakin87]

Looks good