Strings not translatable

Problem/Motivation

I have tried to translate Join group and Leave group from the translation interface but that didn't work for me, seems the t() function was missing.

Proposed resolution

fix.
$build = Link::createFromRoute(t('Join group'), 'entity.group.join', $link_params)->toString();
$build = Link::createFromRoute(t('Leave group'), 'entity.group.leave', $link_params)->toString();