languages: Add .prettierrc to JSON path_suffixes (#50156)

`.prettierrc` can be [written](https://prettier.io/docs/configuration)
in either JSON or YAML. Whether you write JSON or YAML, VS Code will
default to recognizing it as JSON. See screenshot.

Without this change, the user is forced to do:

```jsonc
"file_types": {
  "JSON": [".prettierrc"],
},
```

Small QoL improvement.

| VS Code | Zed (after the changes) |
|--------|--------|
| <img width="1732" height="1125" alt="image"
src="https://github.com/user-attachments/assets/1f9533fc-a77a-40f3-b8a5-6c36faeccffd"
/> | <img width="1732" height="1125" alt="image"
src="https://github.com/user-attachments/assets/bef8ca94-006c-44bd-ac1c-59f915b67123"
/> |

Closes #50072.

Before you mark this PR as ready for review, make sure that you have:
- [x] Added a solid test coverage and/or screenshots from doing manual
testing
- [x] Done a self-review taking into account security and performance
aspects
- [x] Aligned any UI changes with the [UI
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)

Release Notes:

- Added `.prettierrc` to JSON `path_suffixes`

crates/languages/src/json/config.toml

@@ -1,6 +1,6 @@
 name = "JSON"
 grammar = "json"
-path_suffixes = ["json", "flake.lock", "geojson"]
+path_suffixes = ["json", "flake.lock", "geojson", "prettierrc"]
 line_comments = ["// "]
 autoclose_before = ",]}"
 brackets = [