pandoc-3.10: test/command/multiple-metadata-blocks.md

If multiple blocks define a field, the first is used.

```
% pandoc -s -t native
---
foo: bar
...

---
foo: bim
...
^D
Pandoc
  Meta
    { unMeta =
        fromList [ ( "foo" , MetaInlines [ Str "bim" ] ) ]
    }
  []
```