[Doc] update common style

doc.config.js

@@ -30,13 +30,17 @@ module.exports = {
     base: 'vant',
     default: 'icon',
     category: [
+      {
+        base: 'guide',
+        label: '开发指南',
+        include: { common: require('./packages/common/README.md') }
+      },
       {
         base: 'base',
         label: '基础',
         include: {
           icon: require('./packages/icon/README.md'),
           button: require('./packages/button/README.md'),
-          common: require('./packages/common/README.md'),
           loading: require('./packages/loading/README.md')
         }
       },

example/pages/common/index.json

@@ -1,5 +1,5 @@
 {
-  "navigationBarTitleText": "Common 内置样式",
+  "navigationBarTitleText": "内置样式",
   "usingComponents": {
     "demo-block": "../../components/demo-block/index"
   }

example/pages/dashboard/config.js

@@ -3,7 +3,7 @@ export default {
     title: '基础组件',
     content: [
       {
-        name: 'Common 内置样式',
+        name: '内置样式',
         path: '/pages/common/index'
       },
       {

packages/common/README.md

@@ -1,4 +1,4 @@
-## Common 内置样式
+## 内置样式
 Vant 中默认包含了一些常用样式，可以直接通过 className 的方式使用。
 
 ### 使用指南