AO3-7246 Add Parent link to reply comments

[hunternet93]

Pull Request Checklist

• Have you read "How to write the perfect pull request"?
• Have you read the contributing guidelines?
• Have you added tests for any changed functionality?
• Have you added the Jira issue number
  as the first thing in your pull request title (e.g. AO3-1234 Fix thing)
• Do you have fewer than 5 pull requests already open? If not, please wait
  until they are reviewed and merged before creating new pull requests.

Issue

https://otwarchive.atlassian.net/browse/AO3-7246

Purpose

Adds a "Parent" link button to reply / child comments, while also reordering the "Thread" and "Parent Thread" links.

Credit

Hunter Ada Smith (she/her)

[hunternet93]

Regarding the rubocop test failure:

Should I refactor the file to use t() instead of ts() for localization? If so, should I do so for the whole file, or just the changed lines? And would the strings go under [lang].comments.commentable in the YAML file, or elsewhere?

[sarken]

Thanks for working on this!

For larger pull requests, we usually ask people to restrict localization to changed lines. But this is a pretty small, straightforward change, so if you're willing, it would be terrific if you'd localize the whole file!

I think the best place to put it would be under en.comments.comment_actions, similar to the way the text for the comment_form partial is under en.comments.comment_form.