fix(FileSelector): keep edited tab bg height when file name is empty

ref: vuejs#178 (comment)

Author: pdanpdan

src/editor/FileSelector.vue

@@ -239,6 +239,7 @@ function horizontalScroll(e: WheelEvent) {
 }
 .file.pending span {
   min-width: 50px;
+  min-height: 34px;
   padding-right: 32px;
   background-color: rgba(200, 200, 200, 0.2);
   color: transparent;