added task description to title attribute

frontend/src/routes/project/KanbanCard.svelte

@@ -16,7 +16,10 @@
 <div
         draggable="true"
         class={`box prio_${task.total_prio} p${Math.floor(task.total_prio/10)*10} p${task.total_prio % 10}`}
-        {onclick} {ondragstart} style={style}>
+        {onclick} {ondragstart}
+        style={style}
+        title={task.description.source}
+>
     <span class="title">{task.name}</span>
     {#if task.estimated_time}
     <span class="estimate">