No proper API reference is generated for SageMaker SDK v3

**What did you find confusing? Please describe.**
The customer tried to understand the structure of sagemaker.ai_registry.dataset.DataSet and clarify how to configure max context length for datasets used in RLAIF. They failed to do it as no proper API Reference is provided.

**Describe how documentation can be improved**
Please provide proper API Reference asap, otherwise people are lost in the tutorials and have no idea about fine-tuned and advanced system capabilities and configurations. It can be generated automatically from the code.
Example: https://scikit-learn.org/stable/api/index.html.

**Additional context**
Search is not working: Searching for "sagemaker.ai_registry.dataset.DataSet" did not bring any information about the DataSet constructor method and parameters.

Start by locating the sagemaker.ai_registry.dataset.DataSet implementation and the SDK's existing documentation-generation entry points. Compare the expected API reference with the scikit-learn API reference example, then verify that the DataSet constructor and parameters, including max context length configuration, are discoverable through documentation search.

Written by the indexing model from the issue text.