refactor: strengthen type safety

[y-hsgw]

It's a minor change, but I refactored a few parts that caught my attention. Please feel free to close this PR if it doesn't meet your expectations. I appreciate your review!

Checks

• I have read the contributing guidelines.

Changes

• update test case types to use rule-tester types.
  → Due to deprecation of TSESLint's InvalidTestCase and ValidTestCase.

• apply as const for stricter type safety on query definitions.

• add explicit return type to createTestingLibraryRule for better type safety.
  → Because a type error occurred in test files when passing the rule as the second argument to ruleTester.run.

Context

[codecov]

Codecov Report

Attention: Patch coverage is 96.77419% with 1 line in your changes missing coverage. Please review.

Project coverage is 96.28%. Comparing base (26d360e) to head (a90211d).
Report is 26 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/create-testing-library-rule/index.ts	85.71%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1015   +/-   ##
=======================================
  Coverage   96.27%   96.28%           
=======================================
  Files          46       47    +1     
  Lines        2472     2531   +59     
  Branches     1025     1047   +22     
=======================================
+ Hits         2380     2437   +57     
- Misses         92       94    +2     

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[Belco90]

Thanks for taking care of this! Just added some comments.

[github-actions]

🎉 This PR is included in version 7.4.0 🎉

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