Well I did it with out the wp_list_cats. I still don’t get the way that works yet and I may go back and do it that way but…
$link = '<ahref="'.get_category_link($category->cat_ID).'" ';
$rss = '<a href="'.get_category_link($category->cat_ID).'&feed=rss2" ';
if ( $use_desc_for_title == 0 || empty($category->category_description) )
$link .= 'title="'. sprintf(__("View all posts filed under %s"), wp_specialchars($category->cat_name)) . '"';
else
$link .= 'title="' . wp_specialchars(apply_filters('category_description',$category->category_description,$category)) . '"';
$link .= '>';
$link .= apply_filters('list_cats', $category->cat_name, $category).'</a> ';
$rss .= 'title="' . wp_specialchars(apply_filters('category_description',$category->category_description,$category)) . '"';
$rss .= '>';
$rss .= '<img src="https://mouseclone.com/blog/rss-icon/rss-12x12.gif"></a>';
$link .= $rss;
I used $rss to create mine and just copies a few bits of code and then joined the $rss to the end of $link with $link .= $rss
Hope this helps some. maybe i will do it right next time. or maybe not right just what is given to me.
and edit the wp-includes/template-functions-category.php file.
visit website for a look see.