Update README.md

Author: MorvanZhou

README.md

@@ -136,11 +136,14 @@ Tkinter 是 python 自带的可视化窗口包, 可以用来做 simulation 的
 ---
 
 ## 赞助, 让教学变得更好
-```html
+<textarea class="mdhtmlform-md">## Write markdown in the textarea!</textarea>
+<br /><br />
+
 <form style="text-align:center;" method="post" action="https://shenghuo.alipay.com/send/payment/fill.htm" target="_blank">
   <input type="hidden" value="[email protected]" name="optEmail">
   <input type="hidden" value="10" name="payAmount">
   <input type="hidden" name="支持继续制作优质视频" placeholder="付款说明">
   <input type="image" value="submit" src="https://t.alipayobjects.com/images/T1HHFgXXVeXXXXXXXX.png" name="pay"> 
 </form>
-```
+
+<textarea class="mdhtmlform-html" style="display: none;"></textarea>