Show position of merge trains in system notes

Show position always

ee/app/services/ee/system_note_service.rb

@@ -197,7 +197,7 @@ module EE
       body = if index == 0
                'started a merge train'
              else
-               "added this merge request to the merge train at index #{index}"
+               "added this merge request to the merge train at position #{index + 1}"
              end
 
       create_note(NoteSummary.new(noteable, project, author, body, action: 'merge'))

ee/changelogs/unreleased/show-position-of-merge-train-in-system-notes.yml

+---
+title: Show position of merge trains in system notes
+merge_request: 14398
+author:
+type: fixed

ee/spec/services/system_note_service_spec.rb

@@ -343,7 +343,7 @@ describe SystemNoteService do
       end
 
       it "posts the 'merge train' system note" do
-        expect(subject.note).to eq('added this merge request to the merge train at index 1')
+        expect(subject.note).to eq('added this merge request to the merge train at position 2')
       end
     end
   end