Fix #1142: SyntaxWarning: Invalid escape sequences in calibration.py do

[danielalanbates]

Fixes #1142

Summary

This PR addresses: SyntaxWarning: Invalid escape sequences in calibration.py docstrings

Changes

docs/api/metrics.rst                           | 2 +-
 examples/cardiology_detection_isAR_SparcNet.py | 2 ++
 pyhealth/metrics/calibration.py                | 4 ++--
 3 files changed, 5 insertions(+), 3 deletions(-)

Testing

Please review the changes carefully. The fix was verified against the existing test suite.

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This PR was created with the assistance of Claude Agy:Gemini 3.8.flash by Anthropic | effort: high (extended thinking). Happy to make any adjustments!

By submitting this pull request, I confirm that my contribution is made under the terms of the project's license (contributor license agreement).

[MateehUllah]

The raw-string changes look aligned with #1142. One issue with the current PR contribution rules: both ece_confidence_multiclass and ece_confidence_binary are top-level public functions whose docstrings are modified here, and CONTRIBUTING.md requires every new or modified public function to include a >>> usage example. Neither modified docstring currently has one. Could you add a minimal executable example to each and run python tools/check_pr_rules.py --base 1308ac6 --head HEAD?