src/vs/workbench/contrib/notebook/browser/view/renderers/backLayerWebView.ts/BackLayerWebView/find
class BackLayerWebView:	async find(query: string, options: { wholeWord?: boolean; caseSensitive?: boolean; includeMarkup: boolean; includeOutput: boolean }): Promise<IFindMatch[]> {
		if (query === '') {
			return [];
		}

		const p = new Promise<IFindMatch[]>(resolve => {
			const sub = this.webview?.onMessage(e => {
				if (e.message.type === 'didFind') {
					resolve(e.message.matches);
					sub?.dispose();
				}
			});
		});

		this._sendMessageToWebview({
			type: 'find',
			query: query,
			options
		});

		const ret = await p;
		return ret;
	}