Add dom_target helper to create dom_id-like strings from an unlimited number of objects - #55204

Motivation / Background

This Pull Request has been created because it's increasingly necessary to create complex DOM identifiers and the existing dom_id is limited.

This PR creates a new method ActionView::RecordIdentifier#dom_target that can create a unique identifier from an unlimited number of objects, which differentiates it from dom_id which only takes a single object and an optional string prefix.

dom_target(Post.find(45))                  # => "post_45"
dom_target(Post.find(45), :edit)           # => "post_45_edit"
dom_target(Post.find(45), :edit, :special) # => "post_45_edit_special"
dom_target(Post.find(45), Comment.find(1)) # => "post_45_comment_1"

I chose the name of target because I found myself wanting this for generating turbo-rails Turbo Broadcast targets. dom_target is inspired by the structure of turbo_stream_from(*streamables), which concatenates an unlimited number of objects into a single identifier.

Adding an new helper method is proposed as an alternative to adding new behavior to existing dom_id or dom_class helper methods, which had questions/objections. Related:

• Extend dom_id and dom_class to accept var-args #44081
• allow dom_id method to accept an array of records_or_classes #50608
• turbo_frame_tag can no longer accept an array of ids hotwired/turbo-rails#543

Additional information

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one change. Unrelated changes should be opened in separate PRs.
• Commit message has a detailed description of what changed and why. If this PR fixes a related issue include it in the commit message. Ex: [Fix #issue-number]
• Tests are added or updated if you fix a bug or add a feature.
• CHANGELOG files are updated for the changed libraries if there is a behavior change or additional feature. Minor bug fixes and documentation changes should not be included.