flesh out more

apps/docs/docs/advanced.md

apps/docs/docs/api/_category_.yml

apps/docs/docs/end_to_end.md

apps/docs/docs/modules/_category_.yml

apps/docs/docs/modules/high_level/chat_engine.md

apps/docs/docs/modules/high_level/data_index.md

apps/docs/docs/modules/high_level/data_loader.md

apps/docs/docs/modules/high_level/documents_and_nodes.md

apps/docs/docs/modules/high_level/query_engine.md

apps/docs/docs/modules/index.md

apps/docs/docs/modules/low_level/data_loader.md

apps/docs/docs/modules/low_level/embedding.md

apps/docs/docs/modules/low_level/llm.md

apps/docs/docs/modules/low_level/retriever.md

apps/docs/docs/modules/low_level/simple_prompt.md

apps/docs/docs/modules/low_level/storage.md

apps/docs/docs/modules/low_level/text_splitter.md