[feature] add support for generic type

[mlbonniec]

WHY is this change introduced?

To allow returning a custom type instead of the SearchItem

Resolves #72

WHAT does this PR introduce or fix?

Generic type support has been added.

QA Checklist

• I have updated the README.md and related documentation, if necessary

Dependency-specific Checklist

No dependency has been added

Usage-specific Checklist

• The hook's API remains consistent and user-friendly
• Any new features have been documented with clear examples

Release Notes

Note: once this PR is merged, a new release or update might be required for the users.

• The search function now takes an optional generic type.
• keys array is now an array of the generic type keys, so it's improving type completion, and prevent mistakes.

[SMAKSS]

Thank you for the great work. LGTM.

I've included a test framework in the repo. Can you add the respective tests for this change as well? It is much appreciated. 🎉

[mlbonniec]

I've updated existing tests to use a Person type, instead of no type.