docs: fix broken links, add API References (#962)

...arted/starter_tutorial/retrieval_augmented_generation.mdx

...g_started/starter_tutorial/structured_data_extraction.mdx

apps/docs/docs/modules/agent/index.md

apps/docs/docs/modules/documents_and_nodes/index.md

...s/docs/modules/documents_and_nodes/metadata_extraction.md

...docs/modules/embeddings/available_embeddings/deepinfra.md

...cs/docs/modules/embeddings/available_embeddings/gemini.md

...cs/modules/embeddings/available_embeddings/huggingface.md

...cs/docs/modules/embeddings/available_embeddings/jinaai.md

...s/docs/modules/embeddings/available_embeddings/mistral.md

...cs/docs/modules/embeddings/available_embeddings/ollama.md

...cs/docs/modules/embeddings/available_embeddings/openai.md

.../docs/modules/embeddings/available_embeddings/together.md

apps/docs/docs/modules/evaluation/modules/correctness.md

apps/docs/docs/modules/evaluation/modules/faithfulness.md

apps/docs/docs/modules/evaluation/modules/relevancy.md

apps/docs/docs/modules/ingestion_pipeline/index.md

apps/docs/docs/modules/ingestion_pipeline/transformations.md

apps/docs/docs/modules/llms/available_llms/anthropic.md

apps/docs/docs/modules/llms/available_llms/azure.md