Improve numbering format for tips

app/views/exercises/_tips_content.html.slim

@@ -10,4 +10,4 @@
     i.fa.fa-lightbulb
     = t('exercises.implement.tips.heading')
   .card-body.text-dark.bg-white.p-2
-    = render(partial: 'tips/collapsed_card', collection: @tips, as: :exercise_tip)
+    = render(partial: 'tips/collapsed_card', collection: @tips, as: :exercise_tip, locals: { tip_prefix: '' })

app/views/tips/_collapsed_card.html.slim

@@ -1,4 +1,5 @@
 - tip = exercise_tip.tip
+- index = exercise_tip_counter + 1
 .card class="#{exercise_tip.parent_exercise_tip_id? || exercise_tip.rank != 1 ? 'mt-2' : ''}"
   .card-header.p-2 id="tip-heading-#{exercise_tip.id}" role="tab"
     .card-title.mb-0
@@ -7,7 +8,7 @@
           i.fa aria-hidden="true"
           span
             = t('activerecord.models.tip.one')
-            =< exercise_tip.rank
+            =< tip_prefix + index.to_s
             = ": #{tip.title}" if tip.title?
   .card.card-collapse.collapse id="tip-collapse-#{exercise_tip.id}" aria-labelledby="tip-heading-#{exercise_tip.id}" role="tabpanel" data-exercise-tip-id=exercise_tip.id
     .card-body.p-3
@@ -21,4 +22,6 @@
         pre
           code.mh-100 class="language-#{tip.file_type.programming_language}"
             = tip.example
-      = render(partial: 'tips/collapsed_card', collection: exercise_tip.children, as: :exercise_tip)
+      = render(partial: 'tips/collapsed_card',
+              collection: exercise_tip.children, as: :exercise_tip,
+              locals: { tip_prefix: "#{index}." })