Support equivalent of `git_revwalk_hide_cb`

[vlad-ivanov-name]

Summary 💡

https://libgit2.org/libgit2/#HEAD/group/callback/git_revwalk_hide_cb

Related: rust-lang/git2-rs#662

Motivation 🔦

This would allow to hide commits and their parents during rev walk, which is useful for improving performance in certain scenarios.

[Byron]

Thanks for giving an incentive to (finally) expose this functionality in gix as well. I also looked at the linked git2 PR and concluded the lifetime for the pruning/hide filter is suitable.

The functionality is now available in main.

[vlad-ivanov-name]

Awesome, thank you 🙏