Add YAML support

First off, thanks for this polished library.

Since YAML is compatible with JSON, it would be nice if there was an option to use YAML for the error visualization, i.e. instead of this:

```
4 | "content": [
5 | {
> 6 | "type": "paragarph",
| ^^^^^^^^^^^
7 | "content": [
8 | {
9 | "type": "text",
```

Show this:

```
4 | content:
> 5 | - type: paragarph
| ^^^^^^^^^
6 | content:
7 | - type: text
```

Start by examining the library's current JSON error visualization and how its output format is selected. Compare the requested YAML example with existing behavior, then verify that an option produces equivalent YAML-formatted output while preserving highlighted locations.

Written by the indexing model from the issue text.