Lint for likely-malformed reference style links

I often come across the situation in markdown when I accidentally write the following:

[useful text][reference]

[reference](<example.com>)

This, though it might look like a reference style link, is not:

[useful text][reference]

reference

The correct syntax is as follows:

[useful text][reference]

[reference]: <example.com>

useful text

Clippy could lint against this likely-malformed reference link.

Notes:

• This lint should only trigger if [reference](<link>) is on a line on its own (e.g. would be a valid reference target) and reference could be a valid reference key.
• This lint should not trigger if there is any escaping of the in-text part of the reference which makes it not a valid reference link, even if it renders [like][so] in the output.
• I don't think [bracketed][words] would ever be desired except in a code block about markdown, so this lint shouldn't have a lot of real-world false positives.