improve docs to highlight structured data extraction (#9750)

docs/module_guides/querying/querying.md

...odule_guides/querying/structured_outputs/output_parser.md

...le_guides/querying/structured_outputs/pydantic_program.md

...module_guides/querying/structured_outputs/query_engine.md

..._guides/querying/structured_outputs/structured_outputs.md

docs/optimizing/advanced_retrieval/advanced_retrieval.md

docs/optimizing/agentic_strategies/agentic_strategies.md

docs/understanding/querying/querying.md

docs/use_cases/extraction.md

docs/use_cases/multimodal.md