Replace manual activerecord translations with helpers

app/views/proxy_exercises/_form.html.slim

@@ -19,15 +19,15 @@
   .form-check.mb-3
     label.form-check-label
       = f.check_box(:public, class: 'form-check-input')
-      = t('activerecord.attributes.exercise.public')
+      = f.label(:public, class: 'form-label mb-0')
 
   h3 Exercises
   .table-responsive
     table.table
       thead
         tr
-          th = t('activerecord.attributes.exercise.selection')
-          th = sort_link(@search, :title, t('activerecord.attributes.submission.exercise'))
+          th = Exercise.human_attribute_name('selection')
+          th = sort_link(@search, :title, Submission.human_attribute_name('exercise'))
           th = sort_link(@search, :created_at, t('shared.created_at'))
       = collection_check_boxes :proxy_exercise, :exercise_ids, @exercises, :id, :title do |b|
         tr

app/views/proxy_exercises/edit.html.slim

@@ -1,3 +1,3 @@
-h1 = "#{t('activerecord.models.proxy_exercise.one', model: ProxyExercise.model_name.human)}: #{@proxy_exercise.title}"
+h1 = "#{ProxyExercise.model_name.human}: #{@proxy_exercise.title}"
 
 = render('form')

app/views/proxy_exercises/index.html.slim

@@ -1,18 +1,18 @@
-h1 = ProxyExercise.model_name.human(count: 2)
+h1 = ProxyExercise.model_name.human(count: :other)
 
 = render(layout: 'shared/form_filters') do |f|
   .col-auto
-    = f.label(:title_cont, t('activerecord.attributes.proxy_exercise.title'), class: 'visually-hidden form-label')
-    = f.search_field(:title_cont, class: 'form-control', placeholder: t('activerecord.attributes.proxy_exercise.title'))
+    = f.label(:title_cont, ProxyExercise.human_attribute_name('title'), class: 'visually-hidden form-label')
+    = f.search_field(:title_cont, class: 'form-control', placeholder: ProxyExercise.human_attribute_name('title'))
 
 .table-responsive
   table.table.mt-4
     thead
       tr
-        th.p-1 = sort_link(@search, :title, t('activerecord.attributes.proxy_exercise.title'))
-        th.p-1 = t('activerecord.attributes.exercise.token')
-        th.p-1 = t('activerecord.attributes.exercise.public')
-        th.p-1 = t('activerecord.attributes.proxy_exercise.files_count')
+        th.p-1 = sort_link(@search, :title, ProxyExercise.human_attribute_name('title'))
+        th.p-1 = Exercise.human_attribute_name('token')
+        th.p-1 = Exercise.human_attribute_name('public')
+        th.p-1 = ProxyExercise.human_attribute_name('files_count')
         th.p-1 colspan=2 = t('shared.actions')
     tbody
       - @proxy_exercises.each do |proxy_exercise|

app/views/proxy_exercises/show.html.slim

@@ -16,7 +16,7 @@ h2.mt-4 Exercises
   table.table
     thead
       tr
-        th = sort_link(@search, :title, t('activerecord.attributes.submission.exercise'))
+        th = sort_link(@search, :title, Submission.human_attribute_name('exercise'))
         th = sort_link(@search, :created_at, t('shared.created_at'))
     - @proxy_exercise.exercises.each do |exercise|
       tr