#### Fix URL formatting edge cases (#19150 by @andersk)

Avoid corrupting a link, image, or link reference definition with an empty URL and a title, or with certain characters like `<`, `(`, `\`, by using `<...>` wrapping and `\` escaping as appropriate.

<!-- prettier-ignore -->
```md
<!-- Input -->
[link](<> "title"), ![image](<\<(\\>)

<!-- Prettier stable -->
[link]( "title"), ![image](<(\)

<!-- Prettier main -->
[link](<> "title"), ![image](<\<(\\>)
```
