src/vs/workbench/contrib/notebook/browser/notebookServiceImpl.ts/NotebookService/_postDocumentOpenActivation
class NotebookService:	private _postDocumentOpenActivation(viewType: string) {
		// send out activations on notebook text model creation
		this._extensionService.activateByEvent(`onNotebook:${viewType}`);
		this._extensionService.activateByEvent(`onNotebook:*`);
	}