fix: augment Prettier Options types with internal PluginConfig

- Add TypeScript module augmentation for the `prettier` module in `types/index.d.ts` to add the `PluginConfig` interface to the `Options` interface to support proper typing of plugin options in IDEs and during type-checking

types/index.d.ts

@@ -72,3 +72,7 @@ export interface PluginConfig {
 }
 
 export type PrettierConfig = PluginConfig & Config;
+
+declare module 'prettier' {
+    interface Options extends PluginConfig {}
+}