src/vs/workbench/contrib/notebook/common/model/notebookTextModel.ts/NotebookTextModel/_increaseVersionId
class NotebookTextModel:	private _increaseVersionId(undoStackEmpty: boolean): void {
		this._versionId = this._versionId + 1;
		if (!undoStackEmpty) {
			this._notebookSpecificAlternativeId = this._versionId;
		}
		this._alternativeVersionId = this._generateAlternativeId();
	}