title: DRF login button not showing in BrowsableApi
body: <p>I am facing an issue with DRF login button. Although login, registration, and logout functionality are working fine as expected. But the login/logout button is not displaying.</p>
  
  <p>I am using Knox for authentication.
  <a href="https://i.stack.imgur.com/8Jh7I.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8Jh7I.png" alt="enter image description here"></a></p>
  
  <p>what I have done so far</p>
  
  <p>settings.py</p>
  
  <pre><code>INSTALLED_APPS = [
      'rest_framework',
      'knox',
  ]
  
  REST_FRAMEWORK = {
      'DEFAULT_AUTHENTICATION_CLASSES': (
          'knox.auth.TokenAuthentication',
          'rest_framework.authentication.SessionAuthentication',
      ),
  }
  </code></pre>
  
  <p>urls.py</p>
  
  <pre><code>urlpatterns = [
      path('api/auth', include('knox.urls')),
      path('api/auth/register', RegisterAPI.as_view()),
      path('api/auth/login', LoginAPI.as_view()),
      path('api/auth/user', UserAPI.as_view()),
      path('api/auth/logout', knox_views.LogoutView.as_view(), name='knox_logout')
  ]
  </code></pre>