remove unnecessary "tooltip" class from DiffFileTreeItem

Author: wxiaoguang

web_src/js/components/DiffFileTreeItem.vue

@@ -1,5 +1,5 @@
 <template>
-  <div v-show="show" class="tooltip" :title="item.name">
+  <div v-show="show" :title="item.name">
     <!--title instead of tooltip above as the tooltip needs too much work with the current methods, i.e. not being loaded or staying open for "too long"-->
     <div class="item" :class="item.isFile ? 'filewrapper gt-p-1' : ''">
       <!-- Files -->