🐛 Fix styles hiding highlightparent plugin

plugin filename had typo, when z-index: -1 was removed from dokuwiki__content::before side-effects
on highlightparent weren't checked

css/plugins/hightlight_parent.less

@@ -1,13 +0,0 @@
-/**
- * This file provides styles for highlight plugin
- */
-
-
-/* + + + + +  global  + + + + + */
-
-@media @screen_max-md {
-    #plugin__highlightparent {
-        clear: both;
-        margin-top: 1rem;
-    }
-}