title: Rails i18n does not translate from yml the relation name on plural
body: <p>I have this scenario, the <code>person</code> object has a<code>price</code>.</p>
  
  <p>When I try to destroy the <code>price</code> that is being used by<code>person</code>, I can not because it is <code>dependent :: restrict_with_error</code>. (This is expected)</p>
  
  <p>I use yml files to translate error messages from English to Portuguese. But the relationship in the plural is not translated.</p>
  
  <p><strong>Relationship</strong>
  price has_many: people
  person belongs_to: price</p>
  
  <p>Example:</p>
  
  <blockquote>
    <p>obj_price.errors.messages: Não é possível excluir o registro pois existem <strong><em>people</em></strong> dependentes</p>
  </blockquote>
  
  <p>I expected <strong><em>people</em></strong> to be translated to <strong><em>pessoas</em></strong></p>
  
  <p><strong>price.rb</strong></p>
  
  <pre><code>class Price &lt; ApplicationRecord
    has_many :people, dependent: :restrict_with_error
  end
  </code></pre>
  
  <p><strong>person.rb</strong></p>
  
  <pre><code>class Person &lt; ApplicationRecord
    belongs_to :price
  end
  </code></pre>
  
  <p><strong>price.yml</strong></p>
  
  <pre><code>pt-BR:
    activerecord:
      models:
        price: Tabela de Preços
        prices: Tabelas de Preços
      attributes:
        price:
          name: Nome
  </code></pre>
  
  <p><strong>person.yml</strong></p>
  
  <pre><code>pt-BR:
    activerecord:
      models:
        person: Pessoa
        people: Pessoas
      attributes:
        person:
          id: ID
          name: Nome
          price_id: Tabela de preços
  </code></pre>