Wrong rendering of link labels containing [square brackets]

[ViktorSviridenko]

Description

In our project, markdown-to-jsx renders most of the user content, so it's one of the essential libraries.

We faced a problem when we were trying to mark up a page using "footnotes" (like in articles on Wikipedia).

Steps to reproduce

1. Open the official playground;
2. Copy and paste the following code snippet.

You can find it on [Google<sup>[1]</sup>](https://google.com).

You can find it on [Google [1]](https://google.com).

1. Google is the world's largest search engine.

Demonstration and comparison with VS Code

Additional notes

The error didn't occur in markdown-to-jsx@7.1.9.