KHERSON, Ukraine — Scores of people filled the city center Saturday afternoon, celebrating the liberation of the regional capital less than 24 hours after Ukrainian President Volodymyr Zelensky announced that Kyiv’s forces had retaken much of the regional capital from Russian occupation. Babushkas and children waved to arriving soldiers as young men stood on cars, waving Ukraine’s yellow and blue flag. Explosions boomed in the distance, but most of the revelers didn’t seem to notice. They had their city back.