Document missing built-in utility examples

[apples-kksk]

Summary

• add README entries and examples for built-in Record, Parameters, and ConstructorParameters
• move Omit next to Pick in the object operator docs
• clarify that Optional<T> without a key parameter is equivalent to built-in Partial<T>

Fixes #51

Verification

• git diff --check

Docs-only change.

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IssueHunt Summary

Referenced issues

This pull request has been submitted to:

• #51: Improve organization in API documentation

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[gemini-code-assist]

Code Review

This pull request updates the README.md to include documentation and usage examples for several built-in TypeScript utility types, including Record, Omit, Parameters, ConstructorParameters, and Partial. The reviewer provided feedback to ensure consistency in the labeling of built-in types and to correct a duplicate identifier error in the Omit usage example.