Q:

Create a link using the render API

Back in Drupal 7, I was able to create a link  (Ajax enabled) like this:
$page['profile']['links']['videos'] = array(
        '#type' => 'link',
        '#title' => t('Videos'),
        '#href' => 'profile/videos/' .  $uid . ' /nojs',
        '#attributes' => array('class' => array('use-ajax', 'profile-button-videos')),
        '#prefix' => '<div class="profile-bio-link button-profile button-profile-video">',
        '#suffix' => '</div>', 
      );

Though there are plenty of examples about how to create a link from a URI, or external URL; and how to attach attributes, I can't find a shred of documentation on how to append something as simple as "nojs" on the end of the URL... 
My code so far is this in Drupal 8 (and it works).  But, it lacks the /nojs on the end. 
Note: I an not using the the Forms API; strictly Render Elements.  
$url = Url::fromRoute('people.profile', ['uid' => $uid]);
    $render_array['people']['bio'] = [
      '#title' => $this->t('Publications link'),
      '#type' => 'link',
      '#url' => $url,
      '#attributes' => array('class' => array('use-ajax', 'profile-button-bio')),
    ];

The end result should be a link that looks something like this:

/profile/publications/{uid}/nojs

A:

You will not be able to use a route, as /no-js would be its own route.  Instead, you should use Url::fromUri.  You should be able to use:
Url::fromUri('internal:/profile/publications/' .  $user->id() . ' /nojs');

