add rotate function to quicktip chevron icon

resources/less/metager/pages/resultpage/quicktips.less

@@ -186,4 +186,12 @@
             order: 6;
         }
     }
+    .mg-icon-rot180 {
+        transition: transform 0.5s;
+    }
+    details[open] .mg-icon-rot180 {
+
+        transform: rotate(180deg);
+    }
+
 }