Resolve config for the active file

... not for the workspace directory.

Passing a directory to resolveConfig was broken in prettier v3.1.1, as reported here:
prettier/prettier#15879

src/PrettierEditService.ts

@@ -197,7 +197,7 @@ export default class PrettierEditService implements Disposable {
 
     const selectors = await this.getSelectors(
       prettierInstance,
-      workspaceFolder.uri
+      document.uri
     );
 
     if (!isRegistered) {