register(languageId, configuration, priority = 0) {
        let entries = this._entries.get(languageId);
        if (!entries) {
            entries = new ComposedLanguageConfiguration(languageId);
            this._entries.set(languageId, entries);
        }
        const disposable = entries.register(configuration, priority);
        this._onDidChange.fire(new LanguageConfigurationChangeEvent(languageId));
        return toDisposable(() => {
            disposable.dispose();
            this._onDidChange.fire(new LanguageConfigurationChangeEvent(languageId));
        });
    }
@param priority Use a higher number for higher priority