"Add user buttons" button labels are not translatable

Problem/Motivation

On the Multiple Registration Settings, you can "Enable Add user buttons on People page" but that button labels cannot be localized.

Proposed resolution

In multiple_registration.module file, update the multiple_registration_views_pre_view() function:

before (line 556):

    foreach ($available_roles as $role) {
      $result[] = '<a class="button button-action button--primary button--small" href="' . $role["url"] . '">Add new ' . $role["role_name"] . '</a>';
    }

after:

    foreach ($available_roles as $role) {
      $link_label = t('Add new @role', ['@role' => $role['role_name']], ['context' => 'multiple_registration']);
      $result[] = '<a class="button button-action button--primary button--small" href="' . $role["url"] . '">' . $link_label . '</a>';
    }

Remaining tasks

MR is coming.