docs: comment sortablejs solidjs compatibility layer

src/directives/sortable.tsx

@@ -10,6 +10,7 @@ export const sortable = (el: HTMLElement, config: () => Sortable.Options) => {
     const userOnEnd = config_?.onEnd;
     if (userOnEnd) {
       config_.onEnd = (evt) => {
+        // Undoes the dom structure of the list after a drag event. Ultimately this is needed to gain compatibility between sortablejs and solidjs
         if (evt.oldIndex != null && evt.newIndex != null) {
           const parent = evt.from;
           const oldNextSibling =