feat: upgrade comparison / execution test packs to TS 6

[johnnyreilly]

This pull request adds support for TypeScript 6.0, updates dependencies and examples to use newer TypeScript and ECMAScript targets, and makes some minor documentation and configuration improvements. It also introduces new test outputs for TypeScript 6.0 and cleans up some legacy documentation.

TypeScript 6.0 support and ecosystem updates:

• Added TypeScript 6.0.2 to the test matrix in .github/workflows/push.yml, ensuring CI runs against the latest TypeScript version. [1] [2]
• Updated the typescript devDependency in package.json to ^6.0.2.

Examples and configuration improvements:

• Changed the target from es5 to es6 in examples/fork-ts-checker-webpack-plugin/tsconfig.json and examples/project-references-example/tsconfig-base.json to modernize the example configurations. [1] [2]
• Updated src/tsconfig.json to use "moduleResolution": "bundler" and explicitly include Node types.

Testing and compatibility:

• Added new expected output files for TypeScript 6.0 in the test/comparison-tests/aliasResolution/expectedOutput-6.0/ directory, mirroring the structure of the 5.9 outputs to ensure compatibility. [1] [2] [3] [4]
• Removed now-obsolete expected output files for TypeScript 5.9. [1] [2] [3] [4]

Documentation and code cleanup:

• Removed the outdated RELEASING.md file, as the release process documentation is no longer maintained here.
• Updated URLs in HISTORY.md to point to the maintainer's new blog domain.
• Simplified import style for micromatch in src/utils.ts for compatibility with newer module systems.