doc: improve star conversion rate

[TommyLemon]

What type of PR is this?

• bug
• feature
• enhancement

What problem(s) does this PR solve?

Issue(s) number: 0

Description: improve star conversion rate

How do you solve it?

Guide viewer the star.

Special notes for your reviewer, ex. impact of this fix, design document, etc:

Vue.js 作者尤雨溪：“开源的价值并不是那么容易量化，你不主动去要世界也不会给你。”

为什么Patreon上开源领袖Eric Raymond所得到的捐助不到vue.js的 1/10？ - 尤雨溪的回答 - 知乎
https://www.zhihu.com/question/305246119/answer/550207042

Checklist:

Tests:

• Unit test(positive and negative cases)
• Function test
• Performance test
• N/A

Affects:

• Documentation affected (Please add the label if documentation needs to be modified.)
• Incompatibility (If it breaks the compatibility, please describe it and add the label.）
• If it's needed to cherry-pick (If cherry-pick to some branches is required, please label the destination version(s).)
• Performance impacted: Consumes more CPU/Memory

Release notes:

None.