混合使用 ~~~ 和 ``` 时TOC生成异常

[chess99]

markdown文件内容如下时:

# diagram

## sequence
~~~
​```sequence
```
~~~

## flow
~~~
```flow
```
~~~

## flowchart
xxx

生成的TOC为:

- [diagram](#diagram)
  - [sequence](#sequence)
  - [flowchart](#flowchart)

vscdoe devtools里报错:

[AlanWalk.markdown-toc] Accessing a resource scoped configuration without providing a resource is not expected. To get the effective value for '[markdown]', provide the URI of a resource or 'null' for any resource.

Markdown TOC version: 1.5.6
vscode version: 1.40.1

[mcornella]

Can't reproduce in #92.