thanks markdown_index
Press ctrl + p and then enter add-markdown-index .
markdown_index is an extension that can add serial numbers to your markdown title.
Suppose the original text is as follows:
# a
foolbar
## a-b
foolbar
## a-c
foolbar
foolbar
### a-c-d
foolbar
This is code block
## a-e
foolbar
This is code block too
# f
foolbar
Install markdown_index, run > markdown add index, you can automatically add the serial number, as follows:
# 1. a
foolbar
## 1.1. a-b
foolbar
## 1.2. a-c
foolbar
foolbar
### 1.2.1. a-c-d
foolbar
This is code block
## 1.3. a-e
foolbar
This is code block too
# 2. f
foolbar