src/vs/workbench/contrib/notebook/browser/notebook.contribution.ts/NotebookContribution/constructor
class NotebookContribution:	constructor(
		@IUndoRedoService undoRedoService: IUndoRedoService,
		@IConfigurationService configurationService: IConfigurationService,
		@ICodeEditorService private readonly codeEditorService: ICodeEditorService,
	) {
		super();

		this.updateCellUndoRedoComparisonKey(configurationService, undoRedoService);

		// Watch for changes to undoRedoPerCell setting
		this._register(configurationService.onDidChangeConfiguration(e => {
			if (e.affectsConfiguration(NotebookSetting.undoRedoPerCell)) {
				this.updateCellUndoRedoComparisonKey(configurationService, undoRedoService);
			}
		}));

		// register comment decoration
		this.codeEditorService.registerDecorationType('comment-controller', COMMENTEDITOR_DECORATION_KEY, {});
	}