Locale text is not translated

Locale text is not translated in current language

Steps to reproduce

1. Create a new project with default language as FRENCH (not english), maybe this case is outside of your tests.
2. add english language
3. configure url as detection method
4. add block language select: two languages are expected french/english
5. Check translations in admin interface : English -> Anglais, French -> Français : OK
6. display a page in english: OK, both languages in switcher are written in english
7. swith French: KO: French is still displayed as 'French' instead of 'Français', english is displayed as 'English' instead of 'Anglais'.

Proposed resolution

In template 'languageicons-link-content.html.twig', add '|t' as twig translation function for 'text'

{% if placement == 'before' %}
    {{ icon }}{{ separator }}{{ text|t }}
{% endif %}
{% if placement == 'after' %}
    {{ text|t }}{{ separator }}{{ icon }}
{% endif %}
{% if placement == 'replace' %}
    {{ icon }}
{% endif %}