feat(TreeSelect): support show info (#4384)

src/tree-select/test/__snapshots__/index.spec.js.snap

@@ -24,3 +24,13 @@ exports[`height prop 1`] = `
   <div class="van-tree-select__content"></div>
 </div>
 `;
+
+exports[`nav info 1`] = `
+<div class="van-tree-select" style="height: 300px;">
+  <div class="van-sidebar van-tree-select__nav"><a class="van-sidebar-item van-sidebar-item--select van-tree-select__nav-item">
+      <div class="van-sidebar-item__text">group1<div class="van-info van-sidebar-item__info">3</div>
+      </div>
+    </a></div>
+  <div class="van-tree-select__content"></div>
+</div>
+`;

src/tree-select/test/index.spec.js

@@ -150,6 +150,21 @@ test('height prop', () => {
   expect(wrapper).toMatchSnapshot();
 });
 
+test('nav info', () => {
+  const wrapper = mount(TreeSelect, {
+    propsData: {
+      items: [
+        {
+          text: 'group1',
+          info: 3
+        }
+      ]
+    }
+  });
+
+  expect(wrapper).toMatchSnapshot();
+});
+
 test('use sync modifier in main-active-index', () => {
   const wrapper = mount({
     template: `