src/vs/workbench/contrib/notebook/common/model/notebookCellTextModel.ts/NotebookCellTextModel/language
class NotebookCellTextModel:	set language(newLanguage: string) {
		if (this._textModel && this._textModel.getLanguageIdentifier().language !== newLanguage) {
			const newMode = this._modeService.create(newLanguage);
			this._textModel.setMode(newMode.languageIdentifier);
		}

		if (this._language === newLanguage) {
			return;
		}

		this._language = newLanguage;
		this._hash = null;
		this._onDidChangeLanguage.fire(newLanguage);
		this._onDidChangeContent.fire('language');
	}