added styler into default plugin section

The icon does not match the others because the NuvolaX icon theme seems
to have vanished from the Internet. Ideally all those admin icons could
use a replacement. But that should be a different PR I guess.

inc/html.php

@@ -2076,6 +2076,13 @@ function html_admin(){
                     $menu['config']['prompt'].'</a></div></li>');
         }
         unset($menu['config']);
+
+        if($menu['styling']){
+            ptln('  <li class="admin_styling"><div class="li">'.
+                '<a href="'.wl($ID, array('do' => 'admin','page' => 'styling')).'">'.
+                $menu['styling']['prompt'].'</a></div></li>');
+        }
+        unset($menu['styling']);
     }
     ptln('</ul>');
 

lib/images/admin/README

 These icons were taken from the nuvoX KDE icon theme and are GPL licensed
 See http://www.kde-look.org/content/show.php/nuvoX?content=38467
+
+styling.png from https://openclipart.org/detail/25595/brush Public Domain

lib/tpl/dokuwiki/css/_admin.css

@@ -39,6 +39,9 @@
 .dokuwiki ul.admin_tasks li.admin_config {
     background-image: url(../../images/admin/config.png);
 }
+.dokuwiki ul.admin_tasks li.admin_styling {
+    background-image: url(../../images/admin/styling.png);
+}
 .dokuwiki ul.admin_tasks li.admin_revert {
     background-image: url(../../images/admin/revert.png);
 }