Improve rtichoke Great Docs documentation site by addressing style mismatches

- Converted `create_calibration_curve` and `create_summary_report` from Google style to NumPy style docstrings.
- Cleared `style-mismatch` warnings when running `great-docs lint`.
- Ensured proper types, parameters, and descriptions are documented.

Co-authored-by: uriahf <11351434+uriahf@users.noreply.github.com>

Author: google-labs-jules[bot]