chore: bit sponsorship placement

docs/.vuepress/components/Bit.vue

+<template>
+  <p class="bit-sponsor">
+    <a href="https://www.bitsrc.io/?utm_source=vue&utm_medium=vue&utm_campaign=vue&utm_term=vue&utm_content=vue" target="_blank">
+      <span>This project is sponsored by</span>
+      <img alt="bit" src="https://raw.githubusercontent.com/vuejs/vuejs.org/master/themes/vue/source/images/bit.png">
+    </a>
+  </p>
+</template>
+
+<style lang="stylus">
+.bit-sponsor
+  font-weight 600
+  background-color #f3f6f8
+  padding 0.6em 1.2em
+  border-radius 8px
+  display inline-block
+  margin 1em 0 !important
+  a
+    color #999
+  img
+    height 40px
+    margin-left 15px
+  img, span
+    vertical-align middle
+</style>

docs/config/README.md

@@ -4,6 +4,8 @@ sidebar: auto
 
 # Config Reference
 
+<Bit/>
+
 ## Basic Config
 
 ### base

docs/default-theme-config/README.md

@@ -4,6 +4,8 @@ sidebar: auto
 
 # Default Theme Config
 
+<Bit/>
+
 ::: tip
 All options listed on this page apply to the default theme only. If you are using a custom theme, the options may be different.
 :::
@@ -166,7 +168,7 @@ module.exports = {
 }
 ```
 
-::: tip 
+::: tip
   It is worth mentioning that when you disable this option, the corresponding script of this functionality will not be loaded. This is a small point in our performance optimization.
 :::
 

docs/guide/README.md

 # Introduction
 
+<Bit/>
+
 VuePress is composed of two parts: a minimalistic static site generator with a Vue-powered theming system, and a default theme optimized for writing technical documentation. It was created to support the documentation needs of Vue's own sub projects.
 
 Each page generated by VuePress has its own pre-rendered static HTML, providing great loading performance and is SEO-friendly. Once the page is loaded, however, Vue takes over the static content and turns it into a full Single-Page Application (SPA). Additional pages are fetched on demand as the user navigates around the site.