Add and apply rules for multi-line arrays

We were already applying these rules in most cases.

Note we aren't enabling the `MultilineArrayLineBreaks` rule because
we've got places with many elements whire it isn't clear whether
having one element per line would make the code more readable.

app/models/comment.rb

@@ -6,8 +6,8 @@ class Comment < ApplicationRecord
   include Searchable
 
   COMMENTABLE_TYPES = %w[Debate Proposal Budget::Investment Poll Topic
-                        Legislation::Question Legislation::Annotation
-                        Legislation::Proposal].freeze
+                         Legislation::Question Legislation::Annotation
+                         Legislation::Proposal].freeze
 
   acts_as_paranoid column: :hidden_at
   include ActsAsParanoidAliases