How to access a custom field in a field twig loop? I have a content type article which have a field repeatable "related content"

I use a field twig where I have this  loop

{% for item in items %}
    {{ item.content }}
{% endfor %}


It works very well : it displays title of the article and a link to the content. 

I would like also to display some subfields associated with this content but I'm not successful.

I’ve tried things like  :

{{ item.content.field_date_mise_a_jour_article.value }}


but obviously it doesn’t work. item.content only contains url and title.

How can I do that ?

In node--article.html.twig, i can access the related content subfield like that :

{{ node.field_suggestion_articles.entity.field_date_mise_a_jour_article.value }}


How can I do the same in 

field--field-suggestion-articles.html.twig
As you are creating the twig template for a field and try to access the fields / data that is not available, you can write your custom code in preprocess function and you should use the template_preproces_field and create custom variable with desired data and use that variable in custom twig template.

In preprocess function

$variables['myVariable'] = 'My Desired Data';


In Twig use the variable which will print 'My Desired Data'

{{ myVariable }}