src/vs/workbench/contrib/notebook/browser/notebookEditorServiceImpl.ts/NotebookEditorWidgetService/registerEditorDecorationType
class NotebookEditorWidgetService:	registerEditorDecorationType(key: string, options: INotebookDecorationRenderOptions): void {
		if (!this._decorationOptionProviders.has(key)) {
			this._decorationOptionProviders.set(key, options);
		}
	}