Add excluded_content_types parameter to GZipMiddleware

[Kludex]

No description provided.

[Copilot]

Pull request overview

This PR adds the ability to customize which content types should be excluded from gzip compression in GZipMiddleware. It introduces two new keyword-only parameters: excluded_content_types to completely replace the default exclusions, and additional_excluded_content_types to add more exclusions while keeping the defaults. Additionally, it expands the default excluded content types to include already-compressed formats.

Changes:

• Added excluded_content_types and additional_excluded_content_types parameters to GZipMiddleware
• Extended DEFAULT_EXCLUDED_CONTENT_TYPES to include application/zip, application/gzip, and application/x-gzip
• Propagated the excluded_content_types parameter through IdentityResponder and GZipResponder

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

The new excluded_content_types and additional_excluded_content_types parameters lack test coverage. Consider adding tests that verify:

1. Custom content types can be excluded from compression using excluded_content_types
2. Additional content types can be excluded using additional_excluded_content_types
3. The default excluded content types (application/zip, application/gzip, application/x-gzip) are properly excluded from compression

[Copilot]

The documentation in docs/middleware.md should be updated to describe the new excluded_content_types and additional_excluded_content_types parameters. The current documentation at lines 240-244 mentions the default exclusion behavior but doesn't document that these can now be customized.

[Copilot]

Adding new content types to DEFAULT_EXCLUDED_CONTENT_TYPES is a breaking change. While it's sensible to exclude already-compressed formats (application/zip, application/gzip, application/x-gzip), this changes the default behavior for existing users. Consider documenting this as a breaking change in the release notes and ensuring it's mentioned in the PR description or migration guide.