Add autofocus on tag cloud filter input

Fix #1413

tpl/default/tag.cloud.html

@@ -32,6 +32,7 @@
                  {/if}
           autocomplete="off" data-multiple data-autofirst data-minChars="1"
           data-list="{loop="$tags"}{$key}, {/loop}"
+          class="autofocus"
           >
           <button type="submit" class="search-button" aria-label="{'Search'|t}"><i class="fa fa-search" aria-hidden="true"></i></button>
         </form>