Support for MD053: Link and image reference definitions should be needed

Hi,

I'm trying to lint my markdown file and catch a common mistake: I make a typo in the reference e.g.:

```markdown

This is [a link].

[a Iink]: http:/...
```

Currently `mado` doesn't see an issue with it `mado check` but other tools flag it (e.g. `npx markdownlint-cli2`) as [`error MD053/link-image-reference-definitions Link and image reference definitions should be needed Unused link or image reference definition:...`](https://github.com/DavidAnson/markdownlint/blob/main/doc/md053.md)

Of course I'd prefer to stay with mado as I'm really enjoying the experience 😊

Thank you and have a nice day! 👋