Use label in user prefs for accessibility and testability

Author: trichoplax

app/views/users/_prefs.html.erb

@@ -1,6 +1,6 @@
 <% prefs.each do |name, value| %>
   <% pref_config = AppConfig.preferences[name] %>
-  <div class="user-pref">
+  <label class="user-pref">
     <div class="user-pref--meta">
       <strong><%= name.humanize %></strong><br/>
       <span class="desc"><%= pref_config['description'] %></span>
@@ -23,5 +23,5 @@
                data-community="<%= community %>" />
       <% end %>
     </div>
-  </div>
+  </label>
 <% end %>