By SAYED ZIARMAL HASHEMI, RAHIM FAIEZ, JILL LAWLESS and ELLEN KNICKMEYER KABUL, Afghanistan (AP) — Taliban forces sealed off Kabul's airport on Saturday to most Afghans hoping for evacuation, as the U.S. and its allies wound down a chaotic airlift that will end their troops' two decades in Afghanistan. Western leaders acknowledged that their withdrawal would mean leaving behind some of their citizens