The last empty in code block disappear

[deathrush]

Versions

Step 1: write test file bellow:

### test file

\```js
const a = 'b'

\```

there is an empty after `const a = 'b'`

Step 2: change to source code mode and change back.

Expect

Last blank line is reserved

Actually

The last line disappear

• Mark Text: 0.15.0
• Operating system: Windows 7

[Jocs]

@deathrush 为什么需要保留一个空行呢？

[deathrush]

因为代码快里就有这个空行