Further improve handling for code blocks nested in lists

[0xdevalias]

I see that better support for code blocks nested in lists was added in this commit:

• 82e14e3

But if I am reading it correctly, I believe those changes still won't work properly in the case of a code block nested in a list on the same line (which is valid in GitHub Flavoured markdown, and maybe others)

eg.

- This is a list
- It has items
  - ```js
    console.log("Foo")
    ```

See also:

• fix remove_items_in_codeblocks regex for codeblocks nested in lists naokazuterada/MarkdownTOC#170

[derlin]

This is a very good point, thanks for letting me know! I will try to work on this soon.