Moved li tags inside `optional_login`

as per https://github.com/tomchristie/django-rest-framework/pull/1820#discussion_r16987993

rest_framework/templates/rest_framework/base.html

@@ -46,7 +46,7 @@
                                     {% if user.is_authenticated %}
                                         {% optional_logout request user %}
                                     {% else %}
-                                        <li>{% optional_login request %}</li>
+                                        {% optional_login request %}
                                     {% endif %}
                                 {% endblock %}
                             </ul>

rest_framework/templatetags/rest_framework.py

@@ -41,7 +41,7 @@ def optional_login(request):
     except NoReverseMatch:
         return ''
 
-    snippet = "<a href='%s?next=%s'>Log in</a>" % (login_url, escape(request.path))
+    snippet = "<li><a href='%s?next=%s'>Log in</a></li>" % (login_url, escape(request.path))
     return snippet