LaTeX mode creeps in when using JavaScript code snippets

[jcubic]

When having code like this:

---
sidebar_position: 5
---

import CodePen from '@site/src/CodePen';

# Automation

There are few ways to automate the usage of the Terminal.

## Executing Commands

You can execute a command just like the user typed a command:

```javascript
const term = $('body').terminal({
  echo(arg) {
      this.echo(arg.toUpperCase());
  }
});

term.exec('echo hello');
```

After $( JavaScript mode switches to LaTeX.

[christophe-gouel]

I have proposed in issue #31, the addition of a custom variable to deactivate the handling of LaTeX code by polymode. By setting it to nil, this should solve your issue.