Add prepend_mod to TreeController and Api::Repositories

cc @gitlab-com/gl-security/appsec this is a JiHu contribution, please follow the JiHu contribution review process

Thank you for your contribution to GitLab. We believe that everyone can contribute and contributions like yours are what make GitLab great!

Our Merge Request Coaches will ensure your contribution is reviewed in a timely manner*.
If you haven't, please set up a DANGER_GITLAB_API_TOKEN.
You can comment @gitlab-bot label ~"group::" to add a group label.
After a few days, feel free to ask @gitlab-bot help or ping a Merge Request Coach.
Read more on how to get help.

This message was generated automatically. You're welcome to improve it.

added Community contribution label

changed title from Add prepend_mod to tree_controller and tree_type to Add prepend_mod to TreeController and TreeType

	1 Warning
	You've made some app changes, but didn't add any tests. That's OK as long as you're refactoring existing code, but please consider adding any of the ~"type::tooling", ~"tooling::pipelines", ~"tooling::workflow", documentation, QA labels.

1 Message

CHANGELOG missing:

If you want to create a changelog entry for GitLab FOSS, add the Changelog trailer to the commit message you want to add to the changelog.

If you want to create a changelog entry for GitLab EE, also add the EE: true trailer to your commit message.

If this merge request doesn't need a CHANGELOG entry, feel free to ignore this message.

Reviewer roulette

Changes that require review have been detected!

Please refer to the table below for assigning reviewers and maintainers suggested by Danger in the specified category:

Category	Reviewer	Maintainer
backend	Sarah Yasonik (`@syasonik`) (UTC-5)	James Fargher (`@proglottis`) (UTC+13)

To spread load more evenly across eligible reviewers, Danger has picked a candidate for each review slot, based on their timezone. Feel free to override these selections if you think someone else would be better-suited or use the GitLab Review Workload Dashboard to find other available reviewers.

To read more on how to use the reviewer roulette, please take a look at the Engineering workflow and code review guidelines. Please consider assigning a reviewer or maintainer who is a domain expert in the area of the merge request.

Once you've decided who will review this merge request, assign them as a reviewer! Danger does not automatically notify them for you.

If needed, you can retry the danger-review job that generated this comment.

Generated by Danger