Link code_owner deprecation issue in MR approval rules

ee/app/models/approval_merge_request_rule.rb

@@ -11,6 +11,7 @@ class ApprovalMergeRequestRule < ApplicationRecord
 
   validates :name, uniqueness: { scope: [:merge_request, :code_owner] }
   # Temporary validations until `code_owner` can be dropped in favor of `rule_type`
+  # To be removed with https://gitlab.com/gitlab-org/gitlab-ee/issues/11834
   validates :code_owner, inclusion: { in: [true], if: :code_owner? }
   validates :code_owner, inclusion: { in: [false], if: :regular? }
 
@@ -30,6 +31,7 @@ class ApprovalMergeRequestRule < ApplicationRecord
   }
 
   # Deprecated scope until code_owner column has been migrated to rule_type
+  # To be removed with https://gitlab.com/gitlab-org/gitlab-ee/issues/11834
   scope :code_owner, -> { where(code_owner: true).or(where(rule_type: :code_owner)) }
 
   def self.find_or_create_code_owner_rule(merge_request, pattern)
@@ -47,12 +49,14 @@ class ApprovalMergeRequestRule < ApplicationRecord
 
   # ApprovalRuleLike interface
   # Temporary override to handle legacy records that have not yet been migrated
+  # To be removed with https://gitlab.com/gitlab-org/gitlab-ee/issues/11834
   def regular?
     read_attribute(:rule_type) == 'regular' || code_owner == false
   end
   alias_method :regular, :regular?
 
   # Temporary override to handle legacy records that have not yet been migrated
+  # To be removed with https://gitlab.com/gitlab-org/gitlab-ee/issues/11834
   def code_owner?
     read_attribute(:rule_type) == 'code_owner' || code_owner
   end