👨‍💼 We have a combobox that's calling searchCities every render. This function is really slow because it's attempting to intelligently sort thousands of items based on the user's filter input.

Your job is to improve performance by wrapping searchCities in useMemo.

To observe the performance problem with searchCities, open the Chrome DevTools "Performance" tab, click the settings gear and set CPU from "no throttling" to "6x slowdown." Then select any item from the dropdown. Next, click the "Record" circle icon in the devtools to start a recording. Then click on "force rerender" and then click the "Record" circle again to stop the recording. You'll notice that searchCities was called when it should not have been (and it took a LONG time to run). Your goal is to make it so searchCities is only called when the filter changes.