dprint plugin creator

Bridge an existing formatter to dprint; do not reimplement its formatting algorithm. The plugin adapts the formatter's options, input, and output to the dprint protocol.

Core mental model

A dprint plugin is a small adapter implementing four responsibilities:

1. Identity — name, version, config key, schema URL, update URL (plugin_info).
2. Config resolution — read the user's dprint.json slice + global config, produce a typed config and a list of diagnostics for bad/unknown keys. Never hard-fail; diagnose.
3. Format — decode bytes (UTF-8), run the wrapped formatter, return None when the input is already canonical (this is what makes dprint check work) or the new bytes otherwise.
4. Schema — a JSON Schema describing the config, published alongside the artifact.