markdownlint/doc-build/md042.md

This rule is triggered when an empty link is encountered:

```markdown
[an empty link]()
```

To fix the violation, provide a destination for the link:

```markdown
[a valid link](https://example.com/)
```

Empty fragments will trigger this rule:

```markdown
[an empty fragment](#)
```

But non-empty fragments will not:

```markdown
[a valid fragment](#fragment)
```

Rationale: Empty links do not lead anywhere and therefore don't function as
links.