#### Preserve explicit document end marker (#18296 by @fisker)

<!-- prettier-ignore -->
```yaml
# Input
a: a
---
b: b
...
c: c
...
---
d: d

# Prettier stable
a: a
---
b: b
---
c: c
---
d: d

# Prettier main
a: a
---
b: b
...
c: c
...
---
d: d
```