postprocessSync(file, messages, config) {
		const { processor } = config;

		return processor.postprocess(messages, file.path);
	}
Postprocesses the given messages synchronously.
@param {VFile} file The file to postprocess.
@param {LintMessage[][]} messages The messages to postprocess.
@param {{processor:Processor}} config The configuration to use.
@returns {LintMessage[]} The postprocessed messages.